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terry lingle
01-23-2011, 07:28 PM
I have a problem with this 16 hp Kohler engine in my snapper riding tractor.
It started last summer.

what happens is the engine starts and runs normally for from 15 minutes up to 3 hours then the engine instantly is running so rough it will not move the machine then it stalls.
By the time I get the air cleaner off it would start and run fine for the rest of the mowing. I thought Hm heat related it will get worse then be easy to locate.
Fast forward to now. I have a big self powered snow blower mounted on the machine now. I have been fighting this for a week. and want ideas

Ignition Kettering from 12 V battery.

New points coil condenser and plug. Runs better but still shits the bed

Note that during the summer as a lawn mower I was working the engine hard, as a snow blower platform it is just idling,

Carb: I have three and have interchanged them.
Symptom remains unchanged Ditto fuel pumps. Tank is high enough to gravity feed and flow at the carb connection would run a big block at WOt.

I have had the entire fuel system on the bench and looked for floating blockages.
That Carb is about as simple as they get. All three have been soaked ,blown out and set . when on the engine they all set up fine at the correct setting point.

Automatic compression relief has been inspected and is working properly.
valve settings are dead on.
What I have not done is pull the head and check for a sticky valve but that is on the list
any body got a suggestion?

Paychk
01-23-2011, 07:40 PM
Check the plunger rod for the points, I read on the JD site about a smaller Kohler doing the same thing. Something about the plunger swelling and hanging up. The part wasn't available any more & one was fabbed from brass I think.

terry lingle
01-23-2011, 07:56 PM
Good call Paych but that is something I looked at already:(
On this engine that rod not fiber but a hardened steel pin.

I have been lucky enough once to get a timing light on it before it quit.
The light was more consistent than the engine was running.
Immediately after it stopped I cranked it and the light showed consistant spark events.

My approach has been change out everything until it works correctly. Then swap back in the repairable parts until the culprit is identified. that way I know that the spares I have are known good.

Jim-TX
01-23-2011, 09:17 PM
This might not pertain to your engine at all, but I had a Briggs once that started and ran great for a while then it would start cutting out and losing power. I finally replaced the coil and it cured the problem. I had done just about everything else that I could do prior to the coil. It acted very much like it was starving for fuel but it was not a fuel problem at all.

Scotts
01-23-2011, 09:51 PM
New wire from plug to coil? Does this engine have the replaceable wire from plug to coil?

Scott

terry lingle
01-23-2011, 10:09 PM
Scotts:
Yes it has a coil/condenser/points set up the same as the mid 50's cars That is called a Kettering ignition system.

It is all new except the wire which is a solid wire not a resistor wirer it is easy to change except I do not have any and don't want to buy 500 ft of it.

There are no arc overs and the wire can be handled while the engine is running. The original coil was a 12 coil as per Kohler PN.
The replacement is a ballasted coil as specified for a mid 50's chev the condenser is selected for the same application as well.
I did install the ballast resistor and will modify the wiring to take advantage of the hotter spark while cranking but for now I just want it to run reliably.

I will try a resistor wire but after I mod the start circuit as I may lose spark if I use a Resistance wire without bypassing the ballast resistor while cranking.

Scotts
01-23-2011, 10:15 PM
Terry,

Thanks for the info.

Might you have a loose or broken head bolt or warped head? Just throwing things out. Does it seem to act up quicker if it is run at a lower speed?

Scott

terry lingle
01-23-2011, 10:46 PM
When It runs well it is completely normal which pretty much rules out a head gasket problem. but I will get into that area when I inspect the valves and guides.

Taking a compression reading is difficult because it has an automatic compression release that bumps the exhaust valve at low RPM.
There is a cover that can (And has been) be removed to inspect the ACR components they are in good working order.
If I need to go that far into the engine I have a good cam:D but it requires a complete dissassembly to get the cam out :(

These are tough engines but a new 15 hp chonda is only $450.
A replacement Kohler long block is is quoted at $1800 FOB Clearwater which means my problem may still be there after installing the new block if it is in something that is not part of the long block..

The problem is that snapper drives the hydrostatic transmission off the flywheel end and the appliances from the output shaft.
Swapping in any thing else requires making new mounts to put the output shaft in the correct location, A drive adapter for the flywheel end and probably a new shaft for the mechanical drive to the hydrostatic transmission. That is a lot of mods for a simple repower :eek:

Floptop
01-24-2011, 09:58 AM
from 15 minutes up to 3 hours then the engine instantly is running so rough it will not move the machine then it stalls.
By the time I get the air cleaner off it would start and run fine for the rest of the mowing.

Not sure if it pertains, is there a low oil shut down ????.
A problem that intermittant could be an internal fuel line blockage, foreign material in the gas tank, internal short in battrey killing ignition supply current, not sure how crankcase is vented. Valve springs?
Just taking shots in the dark, you've obviously already done a pile of diagnosis here. I have an old Snap On digital oscilliscope that is awsome in these situations as it is portable and can be run off 12 volt, its saved my butt a few times. Anyone near you have one?

terry lingle
01-24-2011, 10:14 AM
Not that I am aware of. (scope)
There are no safety shutdowns on the engine the only interlock is a seat switch that has been bypassed for the duration. All the implement interlocks prevent cranking so not in play here.
My next go will be to redo the ignition /start circuits with a master switch and a separate two section push button start switch so I can eliminate wiring faults and bypass that ballast during cranking. That will allow a new plug wire but I am pretty sure that is not the problem as it is free standing and only close to anything right next to the plug.
After that it is head off and check the valves time:(
Crank is vented through the valve cavity cover into the air cleaner that was inspected when I checked the valve clearance.
Valve springs look good but again will get a closer look when I get into that section.
This has been my focus since it snowed. I need t oget to some other thing for now but I need to keep on this as the next snow fall is just waiting to get me.

moe1942
01-24-2011, 10:44 AM
Typical sympton of a carb needle and seat problem. I have the same problem on a K301. Have kit just waiting on better weather.

terry lingle
01-24-2011, 11:03 AM
Typical sympton of a carb needle and seat problem. I have the same problem on a K301. Have kit just waiting on better weather.

I have tried three carbs one from a known good K301 on a miller welder that I won't need until spring.
All carbs set up correctly to the service manual specs all run good until crap out.
What I have on order at the local small engine shop is two sets of new points and the push rods. two needle -seat sets and a couple of overhaul gasket sets. Delivery date is ?? as he is not a Kohler dealer. I want stock on hand after this is resolved.

moe1942
01-24-2011, 11:21 AM
Terry I have had good luck getting Kohler parts on Ebay. Got two carb rebuild kits for the price of one elsewhere. Also got a $329 crank for a M-16 Kohler for $68 plus shipping. NOS>

Diagnosing your problem is a toughy. I have a 1250 sitting that did the same thing. Running fine then would'nt go above idle. It will sit til the weather gets better. The 1200 has the leaking needle and seat. It too will wait til weather warms up.

grumpy
01-24-2011, 11:47 AM
What I have on order at the local small engine shop is two sets of new points and the push rods. two needle -seat sets and a couple of overhaul gasket sets. Delivery date is ?? as he is not a Kohler dealer. I want stock on hand after this is resolved.

Terry, what few Kohler parts I do buy come from this place: http://www.kohler-engine-parts.opeengines.com/ . I've ordered early Saturday morning and have the parts on Monday, Tuesday at the latest. You might experience differently since your in CN.

terry lingle
01-24-2011, 11:49 AM
I know you can do well on e pay but only if you are buying on "spec" anything you actually need right now is a week away. The cost of parts is not really significant. I burned $45 worth of fuel to get the yard the way I want it.
It is snowing again today already got an inch plus.
Today is ignore it day other things need my attention.

jim hasslinger
01-24-2011, 05:05 PM
Terry; Have you tried opening the fuel cap when the eng tries to die? Could be plugged vent in fuel cap.

JIM

Matt G.
01-24-2011, 05:15 PM
Are all 3 of these carbs correct for a K341? The reason I ask is because the correct carb for a K301 is too small for a K341. There should be number cast into the top of the venturi as you look into the carb as it is mounted on the engine. The K241 and K301 use a #26; the K321 and K341 use a #30. Too small of a carb may be making it run too lean and overheating, which would help the exhaust valve stick. Since a sticky valve is a possibility, I'd use Marvel Mystery Oil as an oil and fuel additive...it can help with the sticking valve.

You should still be running it at WOT with the snowblower or any time there is a load on the engine for that matter. Idling with a load, incorrect ignition timing, etc, or anything else that can cause overheating will exacerbate a sticky valve.

Does the engine start easily and produce good power?

Matt G.
01-24-2011, 05:51 PM
One more thing...have you checked to make sure the valve lash is within spec?

milomilo
01-24-2011, 06:20 PM
Not that I am aware of. (scope)
There are no safety shutdowns on the engine the only interlock is a seat switch that has been bypassed for the duration. All the implement interlocks prevent cranking so not in play here.
My next go will be to redo the ignition /start circuits with a master switch and a separate two section push button start switch so I can eliminate wiring faults and bypass that ballast during cranking. That will allow a new plug wire but I am pretty sure that is not the problem as it is free standing and only close to anything right next to the plug.
After that it is head off and check the valves time:(
Crank is vented through the valve cavity cover into the air cleaner that was inspected when I checked the valve clearance.
Valve springs look good but again will get a closer look when I get into that section.
This has been my focus since it snowed. I need t oget to some other thing for now but I need to keep on this as the next snow fall is just waiting to get me.

I had a similar problem and it traced back to the seat switch I thought I had bypassed. Problem was engine vibration caused it to react intermittently.

TEK
01-24-2011, 06:30 PM
You said you had the fuel system apart, did you check inside the tank real well and rinse it out?

The reason I ask is because I saw one do kinda the same symptoms, a real hair-puller, and it turned out to be a small piece of saran wrap or sandwich baggie material that had somehow made its way into the tank...

It didnt do it all the time, or consistently, and you couldnt see it when you looked in the tank...I just happened to be looking in there wondering about things and saw a slight shimmer of something that didnt belong...fished it out and it never acted up again...

terry lingle
01-24-2011, 07:14 PM
Thanks for the replies guys I will try to respond to each

Jim H I dealt with the vent issue when I bought the machine I used sdie grinder to cut a path up the threads and a good notch in the rim so It is well vented. good thought thanks.
Matt G: yes all three carry the same casting numbers. By visual inspection al lthree have the same internals. By performance on the motor all set up and run the same the motor sounds good until the issue then you are walking.
The snow blower is self contained it has a 15 hp chonda on it .All the tractor
does is push it. I set the throttle for just as much power as needed for hydraulics and travel.
The engine starts good until the failure and seems normal for power
It runs easily accelerates well and sounds right most of the time.
valve lash has been checked and is bang on the service specs

Miliomo:
The seat switch is definitly by passed it has been unplugged from the harness under the dash and a jumper installed in place of it. good call though
Tek: the fuel tank was rinsed and scrubbed then refilled with fresh fuel with a llttle methyl hydrate added to absorb any residual water

kbs2244
01-24-2011, 08:16 PM
If you are at low RPMs you are at high vacum.
Check all along your intake system for something that maybe "flapping."

rmack898
01-24-2011, 08:37 PM
I had an intermittent problem with a fuel system that kicked my butt for over a week. I had the complete fuel system apart many times (over 10) and could not find anything wrong or out of spec. Got me so pissed that I went back to the beginning and tore it apart again and went through everything with a magnifying glass (literally). I found a tiny piece of teflon tape that had migrated to a position that it would act as a flapper valve intermittently in the needle seat. Teflon tape is totally transparent when soaked in gasoline.

That job kicked my butt for over a week and it turned out to be something so small, I overlooked it many times over.:o

A reminder to all, Teflon tape has no place in a gasoline fuel system.

Tom Zachman
01-24-2011, 08:50 PM
Teflon has no place in any part of our lives. At best it's lubricant and it's never a sealant. With the exception of the water molecule as it turns from ice to water, teflon is the most antisocial molecule. The water/ice thingie wins because it is self-lubricating.

Oh, teflon sucks with eggs and bacon, too.

Roddo
01-24-2011, 09:47 PM
From reading your post it sounds like you have a ballasted coil an and a ballast in line. Could this lower the voltage to the points causing problems as it gets hot.

Jim-TX
01-24-2011, 11:14 PM
Teflon has no place in any part of our lives. At best it's lubricant and it's never a sealant.

I'm a little curious as to why you say this. I've had very good results with teflon tape on everything from air to hydraulic connections. When we were farming I used teflon tape on 2000 psi hydraulic connections. It sealed and didn't "weld" the connection where it couldn't be undone. Last week I was helping a friend plumb a powder coating oven. We were running 1 1/4" black pipe for propane and had a particular fitting that was leaking. The pipe dope in a can wouldn't stop the leak but teflon tape did.

terry lingle
01-24-2011, 11:15 PM
Thanks again guys I haqve been out and about most of the day and will be gone tomorrow as well
I am compiling a list of items that I may not have fully checked and ideas not yet considered.
again I will take each comment in turn.
KBS2244
The entire intake is about 3.3/4 inches long with most of that inside the carb.
I have run the engine with the air cleaner on and off makes no difference Three different carbs no difference . With the carb off I can see the bottom of the valve face in my inspection mirror.

RMack 898 You are absolutely correct about Teflon All fittings are either jic, hose on pipe or dry seal threads no Teflon rtv pipe dope or other introduced gunk in or on the fuel delivery system.

Tom Z we do agree on that

Roddo Due to availability issues I had to convert to a ballasted coil ignition system. I got the coil ,condenser and ballast resistor specified for the same vehicle so there should be no voltage issues when running.

To be clear a ballasted coil is designed to operate correctly at 6-8 volts on the coil. the ballast resistor is selected to provide that correct voltage level from a battery that is being charged by the motor being run. The battery voltage can go from 11.8 v at loaded idle to 14.5v at operating speed with the regulator cold.

When we are cranking the engine the voltage at the vehicle pick off point (nominally the power terminal on the starter) can be as low as 8 volts.
that is why the ballast is bypassed during starting. the result is full spark during cranking.

Point voltage in Kettering ignition systems is actually quite high when the points open it is in the 400 volt ac range. The condenser is there to protect the points and control the energy across the points preventing damage and extending point life to reasonable limits. That is why I got the condenser that matched the coil.

Current flows through the coil and points for most of the spark cycle. The design in general wants 4-6 amps as the peak coil current for either ballasted or un ballasted coils.

As long as this current is reached we will get full design spark energy. The difference in the voltage at the coil is compensated in the design of the coil.

When the points open the energy stored in the coil over the relatively long charge period is delivered to the plug almost instantly.

The remaining factor is that the current does not rise instantly to its stable state level of 4-6 amps but rises logarithmically as the magnetic metal core in the coil stores energy. This is the energy delivered to the plug.

In a properly designed coil such as the one i am using it is designed to give full spark till about 5000 rpm on a V8 engine. in a real car other factors such as mechanical instability around the point-cam advance plate interface come into play that will dominate the spark cycle before the coil does

500 RPM is 2500 X 8 /60 spark events per second or 333per second
that gives the coil about .003 second to charge to full operating current.

On a one cylinder such as this at 3000 rpm we have only 25 spark events per second giving almost thirteen times as long.
In fact the v8 idling at 600 rpm is equivalent of the 1 cylinder at 4800 rpm from the ignition systems perspective.

As to heating idling causes most of the coil heating to occur in the primary winding whereas high speed operation within design limits does not lower the primary related heating significantly but does raise the secondary heating a lot Because each spark event imparts the same amount of heating energy to the coil
The points and wiring see pretty much the same current with either coil and across the entire operating range of this engine.

I am using some of the questions to clarify an remember hard earned knowledge from that era. Pleas keep ideas comming. This thing is simple compared to most engines yet it is resisting. RESISTANCE IS FUTILE
VE VILL VIN

Harvuskong
01-24-2011, 11:50 PM
Hello Jim-TX,

I quit using the Teflon tape years ago as much as possible.

I switched to the Permatex Thread Sealant with PTFE - Teflon.

It has worked well. Applies with a brush. No wrapping around and around with tape.

I use it on Hyd hoses and other stuff on the farm. It is a universal size. Can be wide or narrow. And it does not shred either.

Adjustments can be made up to 24 hours after application without damage to seal.

http://www.permatex.com/documents/tds/Industrial/80632.pdf

I will say that this is the first time that I have ever read any thing really negative said about Telfon other than when it is a contaminate in a hyd or fuel system.

terry lingle
01-25-2011, 12:39 AM
Teflon tape when very carfully applied will seal well to reasonable pressures.
The problems I have seen related to two areas first contamination.
This is always a quality control issue the user lets a little tape get loose in the system.
Sometimes it is tape that was on the joint from before and not properly removed sometimes just carelessly installed.

The second issue is the friction reduction Teflon tape imparts in a joint.
This can result in one extra turn and a cracked female thread part.

Here if you are plumbing propane with pipe threads the code calls for yellow tape plus propane rated Teflon paste There are code requirements for joints designed to allow inspectors to see at a glance that procedure has been followed.
RTV and other liquis sealants must be carefully used as well or you can destroy an engine or puimp when the excess lumps get into the wrong places.

Gadgeteer
01-25-2011, 01:34 AM
Terry,

1. I've read that you modified the gas tank cap to allow for venting, but would you mind humoring me and try running the engine with the cap removed to see what happens?

2. Does the problem arise, regardless of the amount of fuel in the tank?

3. Also, suggest you run a gas line, straight from the tank to the carb, eliminating the fuel filter, as one more method to isolate a possibly bad component.

Paychk
01-25-2011, 02:34 AM
One of the guys @ the JD site chased something similar and and it was Gasohol not playing nice with the disposable see through paper fuel filters. He went back to the sediment bowl type and the problem went away.

Do you have the alcohol/gas in Canada and if so can you get 100% straight gas to try?

Tom Zachman
01-25-2011, 04:40 AM
I'm a little curious as to why you say this. I've had very good results with teflon tape on everything from air to hydraulic connections. When we were farming I used teflon tape on 2000 psi hydraulic connections. It sealed and didn't "weld" the connection where it couldn't be undone. Last week I was helping a friend plumb a powder coating oven. We were running 1 1/4" black pipe for propane and had a particular fitting that was leaking. The pipe dope in a can wouldn't stop the leak but teflon tape did.

Jim, I think teflon is a great lubricant and a terrible fried chicken additive.

terry lingle
01-25-2011, 08:24 AM
Gadgeteer:
Gas cap off is a little problematic as There is no hood on the unit when the snow blower is mounted so I can get at the dipstick and add oil if needed.
With the cap off any splash would get on the engine and could cause a fire.

Also the blower puts me in a big snowstorm when in use and this would cause significant amounts of snow to get into the tank .
I will look and see if I have a molded rad hose I can clamp over the tank opening to control slosh and prevent snow from getting into the tank.
A hose directly from the tank to the carb is in the list of things to try.
Good calls they are added to my list.

The problem happens any time from 15 min to three hours into a tank of fuel .
I can mow about 3.5 hours on a tank so probably can run 5 plus with the blower mounted so I would say fuel level seems to have little or no bearing.
I top up both fuel tanks when ever I can as I hate running out of fuel and needing to get out a gas can the pump is right next door.

I looked and am amazed that I have no pictures of this set up as I am sure I took some . Will get a couple and post them as soon as I get time.

Paychk
Gasohol is available in Canada . I get my fuel direct from the pump next door pure gas so far as I know l. There are a lot of small engines fueled from that pump with no reports of fuel related issues and I would hear as I get to work on 95 % of them.

The filter on this is not a see through plastic filter it is a metal canister suction filter not sure what it fits but it is definitly from a 2005 or newer vehicle with the hi pressure pump mounted on the frame rail.
Got a few at a yard sale all new a plastic in bag inside a motocraft box.

The can holds a pint of fuel. I see good fuel flow through the delivery sytem when ever I disconnect the carb and turn the fuel shut off on. That shut off is a 3/8 brass 600 PSI WOG ball valve. If the fuel were affecting the filters it should be a permanent event once plugged it should remain plugged.
Every time I put a hose on I let a little fuel flow into a clean container to purge any loose shit from the lines.
I will ask the owner to be certain it is pure gas. Good point
Again thans guys something will show up the culpret

Lu47Dan
01-25-2011, 09:22 PM
Terry, could one of the fuel lines have a flap of liner material that is restricting the fuel flow? I have seen hydraulic hoses skive and block flow before and a fuel line on a 1971 Chevy Nova that had the same condition. Once the pressure dropped off the flap would return to normal and the system would work again until the next time it would rear its ugly head.
It sounds as if it is one of those "Oh, shit!" problems that confound us once in a while. :devil:
Dan.

terry lingle
01-25-2011, 10:28 PM
Yes it is a puzzler The fuel system has been subject to a lot of very close scrutiny including a complete visual and air blast checks. I am planning to completely bypass the system with a new line from tank to carb.
THe problem with adding diagnostic tools is the randomness of the fault added to the current useage as a snow blower There are some things that I have avoided looking into due to lack of gaskets like valves and build up in the combustion chamber. The snow has quit falling and it is warm so I have a little time and can explore a little further. a random sticky valve could do this.
thanks for the suggestions.

Matt G.
01-25-2011, 10:43 PM
Seeing as how you've checked just about everything else, I'm starting to lean towards it being a valve issue. I've probably had 40 or so K-series Kohler engines in Cub Cadet tractors, and I've not had a problem quite like this. There was a guy on one forum I belong to that was experiencing something similar with a K301. He has checked/replaced/rechecked everything except the valves.

Paychk
01-25-2011, 10:48 PM
Something else that may help to narrow down is keep a can of ether handy; when it dies, shoot a little ether into the carb and crank. If it fires on the ether then you know absolutely it has to be fuel caused. If it fires and blows out the exhaust you'll know that valve is hanging open, same for the intake.

Gadgeteer
01-25-2011, 10:57 PM
Also, when the engine starts to sputter, try choking it a bit to see if it will recover. If it does recover, that indicates a sparse fuel supply.

terry lingle
01-25-2011, 11:02 PM
Yes that is a way to detect sticky valves . I was set up for that exact test but the ether can fell out of my pocket into the snow the next pass it went about 100 ft and put an entire flock of snow sparrows to sleep:D
scarred the crap out of me too.
Valves move up the list.
As I have said before by the time I get to the choke it is too late cold - blowing snow - heavy mitts some things are not possible

CEC
01-25-2011, 11:22 PM
Terry,
I've been reading your thread. I wish I could give you some help here. But, I'm stumped on what could be your trouble. My first guess would have been vapor locking.

terry lingle
01-25-2011, 11:30 PM
My first guess was ignition followed by fuel system.

If I had a dollar for every thought I have had about this thing I could put in a raised solarium and hire a contractor to clean the yard while I relaxed in my recliner and watched :D

CEC
01-26-2011, 07:14 AM
I had something similar (maybe) once on my zero-turn (17 hp B&S). Ended up being old fuel line collapsing between the filter and the tank when the engine was running. With the engine off I could pull the line of the Carb and have plenty of free flowing gas. I hunted that problem for quite some time before I saw the line collapse.

terry lingle
01-26-2011, 09:26 AM
I would think that as soon as the line opened up it would run fine again. Thyiss thing must cool for at least 10 -15 minuets or considerably longer than it takes to change the carb.

There is another electrical possibility that I have ruled out, that is a discharged battery issue. the Kohler has a 15 amp charging system complete with an ammeter which shows a discharge while cranking and a charging condition while running. The chonda on the blower also has a charging system and is using the same battery. both systems are basic brute force systems. running the chonda up to speed reduces the ammeter indication on the Kohler.
some times the failure has caught me in the wrong place and I have had to use the starter to get the lift to work so I could get the machine into a safe spot. Cranking was normal and crank time was much longer than for a normal start.

lars66
01-26-2011, 09:58 AM
We had a Mercury that broke a valve spring in the first coil above the flattend end, the break was on a very long diagonal. The car would run like a top then run so bad it would struggle to get over a hill. Several mechanics tried to diagnose the problem but it was only solved when we left it for about two weeks with a mechanic to be his daily driver.

terry lingle
01-29-2011, 07:50 PM
I took another go at this problem yesterday after I got caught up with the other little jobs.
I pulled the head and took a close look at the valves.
I pulled the valves out cleaned and polished the stems lapped the seats checked the springs and rotators things looked perfect before Ii started but it is good to know that the valve train is clean and in spec.
For information the following specs were confirmed,
1 crossover at TDC this confirms that the cam is installed correctly.
2 intake lift .322 spec .318
3 exhaust lift .324 spec .318 these measurements confirm that the cam is fine.
4 Valve lash is .009 intake and .019 exhaust as per the Koehler service manual.
5 The ACR is observed to bump the exhaust valve .025 at low speed cranking.
This confirms that the ACR is working to reduce compression for starting.
Earlier visual inspection of the ACR components showed them to be in good shape and identical to those on a cam in a known good engine.

Head gasket was checked and reused as it was in excellent shape. Although a new gasket is on order.

For information the K301 intake valve is the same as the 341 but the exhaust valve is larger.
The head on the 341 has an extra head bolt and a different torque pattern

I have some pictures now
1 gas tank vent( the slot extends below thread depth and below the last thread on the cap)
2 intake valve as removed
3Cylinder area valve reinstalled but not cleaned build up in the engine is minimal Less than .015 thick.
4 the 42 inch 15 hp self powered snow blower.

That thing uses all 15 hp and throws snow 60 -100 ft :D
I extended the discharge to clear the motor.
The chute swings 45degs behind the machine both ways and is electric motor actuated.

Dr Dean
01-29-2011, 10:03 PM
I think you went to deep. From my experience it really sounds like an ignition problem. Years ago I had an Onan engine that would run great for a bit then it would have a severe power loss and would eventually die. It turned out to have a failed condenser. I lost my ass on that job but I also learned a valuable lesson, even though the part is new it may not be any good.

cutter
01-29-2011, 10:22 PM
Years ago I had an Onan engine that would run great for a bit then it would have a severe power loss and would eventually die. It turned out to have a failed condenser.


Thank you, Dean. :D
Ol' Yaller was behaving exactly that way last time I had him running.
Now he has a fuel problem too, overflows the float bowl.
I just parked the little tractor last summer, disgusted with the whole deal.
I'll see what I can do about that later this year.

terry lingle
01-29-2011, 11:00 PM
I think you went to deep. From my experience it really sounds like an ignition problem. Years ago I had an Onan engine that would run great for a bit then it would have a severe power loss and would eventually die. It turned out to have a failed condenser. I lost my ass on that job but I also learned a valuable lesson, even though the part is new it may not be any good.

Already replaced the entire ignition system except the steel cored spark plug wire it checks fine and shows no corona effect at night. The only change I made was to switch to a ballasted coil as there were no non ballasted coils available. This engine has a standard kettering ignition system the same as mid 50's vehicles.
The ignition seems very stable and the spark is hot. I matched the condenser to the new coil. See earlier posts.

terry lingle
01-29-2011, 11:14 PM
what engine is in old yaller ?
Most small engines use a form of magneto ignition with most of the components buried under the shroud or even under the flywheel.
AS an example of how far i will go to fix something that is basically sound but has had a cost fatal failure:
I have a craftsman with a Tecumseh in it that had an integrated electronic ignition /charging module in it.
The module went out and queers wanted more than the machine was worth for the part.
I gutted the module and rewound the trigger coil to give a solid pulse into the electronic ignition from a chev inline engine . It is HEI but the coil is stand alone. End result was hot stable spark for less than an hours work.

cutter
01-30-2011, 02:58 AM
what engine is in old yaller ?
Most small engines use a form of magneto ignition with most of the components buried under the shroud or even under the flywheel.


It's the old 2 cylinder Onan, Terry. Yaller is another Sears Suburban like the Whiteboy. I've rebuilt the mowing deck from a rotted out mess and, built a new dash tower and grill/nosepiece back when the engine was trying to cope.
Oh yeah - new tires, drive belt & new seat, and I relined the brake which required dropping the rear end. :rolleyes:

The ignition has pushrod driven point with 2 coils & is located on top of the engine - not amenable to easy conversion. :)
It was burning a little oil but it does run sweet when it runs.
That's a little bit like my favorite old vaudeville joke though:
"If we had some ham we could have ham & eggs - if we had any eggs."

terry lingle
01-30-2011, 08:39 AM
I have a couple of Onans here with that ignition system. it is a "wasted spark" system. Both coils fire every time the points open giving a spark at the correct time plus one at the end of the exhaust stroke. It could be converted but there is no reason to convert it as long as parts are available and they are.

I would get a points and condenser set from Onan and do both as a failed condenser will damage the points pretty quickly. The condenser probably is a different value because of the coil design. check that push rod for damage and wear as a set of closed points will also give similar symptoms.
Those Onans were used on a lot of equipment welders, generators,pumps small tractors and almost any other industrial machine needing that much HP.

That tractor is the big brother of the one I converted the ignition on it has the same profile and coloring. Good luck with it .

terry lingle
02-08-2011, 01:26 AM
I woke up this morning to an awful sight +2 C on the thermometer ( at 4 AM ) and 5 inches of white slop:(
5 hours and 5 gallons (20litres)of gas later it has all been blown away but the temp was +8 and I was blowing slush :D:D This should have taken about 1.5 hours and 6-8 liters with normal snow.
The kohler ran perfectly except when the new coil went open:mad: but that was an easy fix. absolutely no sign of the intermittent that has been plaguing it .

What has been done since it was last used

1 pulled the head and valves quick lapped the valves to check for problems
polished the stems and cleaned up inside the cylinder. Nothing was seen that indicated a problem. reassemble and set valves. no new parts used . the original valve settings were correct.

2 The ignition/start wiring needed modification to accommodate the ballasted coil so I drew up a schematic and did it up with all new wiring (Again) as that was easier than kludging in the extra wire for the ignition.
Checked all switches ,terminals and wires removed for a cause nothing was found so the complete harness was saved for reuse if needed.

This morning I fired it up tweaked the carb ( it had been off for the valve work) and started clearing the snow.
About 3 hours later the Kohler stopped. but not a distressed engine that dies it just stopped.

No spark 12 v on the coil + ground (points closed ) or random (Points open ) on ciol - pull new coil yep open primary . No heat indication so it is just an internal termination failure. Install new coil and we got 5 volts with points closed so ballast is fine and 12 volts when cranking( on coil +) plus good hot spark. The voltages were checked by hand rotating the engine to get points closed and disabling the starter solenoid to static check wiring to coil.

This leaves me wondering? valves ? intermittent coil ? that would mean the original coil had essentially the same fault as replacing it along with the rest of the ignition system resulted in better running until the fault showed then no difference in fault event.

I can and will swap in the old parts one at a time to see which if any are FUBAR If nothing else shows up then it had to be valve train related.

Floptop
02-08-2011, 09:45 AM
intermittent coil ? that would mean the original coil had essentially the same fault as replacing it along with the rest of the ignition system resulted in better running until the fault showed then no difference in fault event.



Thats very plausible, although hard to believe.
Glad you got her to do a days work.

CEC
02-08-2011, 10:32 PM
Terry,
If you having failure on the primary side of the ignition coil, check the grounding of the coil. I ran into that once on a Ford.

Tom Zachman
02-08-2011, 10:40 PM
Terry,
If you having failure on the primary side of the ignition coil, check the grounding of the coil. I ran into that once on a Ford.

We once had a Ford who wasn't grounded. We tried rehab; but finally had to let her go.

CEC
02-08-2011, 11:30 PM
We once had a Ford who wasn't grounded. We tried rehab; but finally had to let her go.

But... didn't they still name a clinic after her?

Tom Zachman
02-08-2011, 11:45 PM
But... didn't they still name a clinic after her?

$he $till ha$ a clinic named after her.

terry lingle
02-09-2011, 12:37 AM
Cec when I installed that coil I sanded the contact area on both the coil and the bracket. Then made sure the coil was properly secured in the bracket.
The working voltage on the coil was correct between 6 and 8 volts . I had it off the motor within three minuets of failure. There was no excess heat or hot spots. My best guess is that one end of the primary was not properly welded to the terminal and it separated.

boilerman
02-09-2011, 01:01 AM
Just got done reading this thread and to tell you the truth, I was guessing a loose valve seat....run into it a few times and the engine acted just as you was saying.

terry lingle
02-09-2011, 08:30 AM
I have seen loose seats before. I checked for evidence of that as well as cracks.everything in there looked perfect. OHV engines with aluminium heads are prone to loose seats due to heat expansion

CEC
02-09-2011, 12:33 PM
Terry,
How about the ground connection on the block?
I know some of what I suggest are the simple things... But sometimes it is the simple things that we overlook.

terry lingle
02-09-2011, 01:02 PM
cec: Thanks
Simple suggestions like simpler questions are never dumb or unappreciated.
This motor sits in a cradle on rubber mounts. The ground is via a large braided copper strap from the foot bolt to the motor mount bolt. Both bolts are tight
and cranking is reliable .
Non of the other systems that depend on that ground have shown any symptoms.
I think I will relocate the ground to the engine and let the off engine accessories use that ground.

The Chonda uses the tractor battery for starting and also has internal brute force charging.
When running it shares the charging with the Kohler as shown by reduced charging current on the snapper's ammeter.
The electric chute rotator also uses battery power
current returns via the frame of the blower and a ground strap from it to the snapper frame.