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Shu

Engine cutting out and dying when hot

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Shu

I have a 1996 Wheel Horse 314H with the Kohler M14.  It has had an issue for a few years now where after it gets hot it starts to misfire, stall and eventually die.  If I cool it down; leaf blower, it will start up and run again until hot.  I have replaced the ignition module/coil, spark plug, carburetor, fuel line, fuel pump, ignition switch, battery and it still does it.  It has to be hot outside too.  Will not do it on a cooler day.  Seems to be worse on rougher terrain.   Is there a temperature sensor on the M14?  Any other thoughts on the cause.  It runs GREAT, burns no oil, starts right up, and it is in remarkable condition; just this one issue.  

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SylvanLakeWH

:text-welcomeconfetti:

 

Gas cap vent clogged?

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953 nut

:WRS:

Could be the cooling fins on the cylinder are partly clogged by grass clippings or a rodent nest. Remove the engine tins and clean them out to allow proper air flow.

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8ntruck

Sounds like a heat issue, or maybe a vapor lock issue.

 

Like @953 nut says, make sure the cooling fins are clean, then take a look at the fuel line routing.  Does it go anywhere near the exhaust system?

 

:text-welcomeconfetti:to the forum.  Good folks here.  Combined, the members on the forum have probably broken and fixed anything that can be broken on a Wheel Horse.  They are more than willing to give advice, too.

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roadapples

:WRS:

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Bill D

Are the valves adjusted correctly?  Is a valve sticking when hot?  Does it loose compression until it cools down.

Also, do you have the thick plastic spacer/gasket between the carb and the block?  If not that could be causing a vapor lock issue if the carb gets too hot.

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gwest_ca

Have you checked the ignition wiring? There is a diagram just for it. The seat switch controls a relay on this model.

Do not allow any battery voltage into the ignition wire. The ignition wire simply grounds the ignition to shut it off. If you can disconnect and isolate that wire close to the engine it should run but not shut off.

 

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ranger

My 312-8, with Magnum engine, had the exact  same issue. I had fitted a stainless steel silencer, (copying the original), this retained the heat from the exhaust more so than the mild steel original, causing the exhaust valve to stick in the open position. Early Magnum engines required the exhaust valve guide to be reamed slightly larger. Next time it occurs, pull the spark plug, (ex valve underneath, tap the valve head, and see if it closes). The funny thing was mine reacted just the same over rough ground??? I had tried everything, and one day as it cooled, I heard a load, ‘Click’ as the valve closed’  My cure was a more free flowing silencer that didn’t retain as much heat, or obstruct the cooling air flow out of the engine. Perhaps you have a silencer that is partially blocked, or valve/guide that needs a de-coke?

Doug.

p.s. Welcome to Red Square.

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Shu

Thanks for the welcomes.  
Thank you for the great suggestions.  

I have had the tins off the engine looking for some sort of temp sensor.  All looked good under those.  I'll pull and check again just in case though.  

I had previously by passed the seat switch and had same results.  

I tried to remove the gas cap when it starts stumbling and it provided no help

I was worried it could be a sticking valve.  I will have to check this out.   hopefully just something in the exhaust.   

It is 100% all stock and in incredibly clean shape.  It mows incredibly well too.  I have a newer JD mower and never like using it because this does such a better job.  

IMG_3942.JPG

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ranger
Posted (edited)

One thing I forgot to mention. When the issue occurred, trying to restart the engine, it spun over much easier, and when the key was released, the engine coasted to a stop, rather than stopping quickly as it came up on compression. This confirmed my suspicion of a sticking valve. Running with a more open exhaust also showed me the silencer was the reason for said ‘sticking’ valve.

Edited by ranger
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953 nut
41 minutes ago, ranger said:

trying to restart the engine, it spun over much easier, and when the key was released, the engine coasted to a stop, rather than stoping as it came up on compression.

A stuck open exhaust valve for sure.   Odd that Stainless Steel muffler would hold that much more heat. 

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peter lena

@Shu welcome to the site !  agree with others  with search ideas , while thats going on , personally , would do a fuel additive to possibly assist in valve stem cleaning / sticking area . when ever I  look at a problem I  go after any possible related area , usually finding the problem, only my Idea. typically running in a used engine on a separate gallon of heavily treated gas . the condition of that is very good , take advantage of that and  verify and insure all of its operation , especially wiring issues , tightly bent chafing spots , any corrosion , dielectric grease , cracked electrical connections . think its a fuel related issue , gummy residue , I  add stabil to every drop of my fuels , hope you find it , pete 

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ranger
42 minutes ago, 953 nut said:

A stuck open exhaust valve for sure.   Odd that Stainless Steel muffler would hold that much more heat. 

I had copied the original down to the size and number of holes in the baffles. When I took it off, the stainless ‘bend’ I temporarily replaced it with, had too large a bore, so I heated one end red hot with a torch, and ‘forged’ the pipe to a smaller I.d. I held the other end in my hand (no gloves) whilst doing this, the end I was holding was only about, 10”-12” away from the ‘hot’ end. No apparent heat transfer felt, and it was not a ‘five’ minute job, try that with mild steel or copper! Stainless doesn’t conduct heat very well. If the silencer had been on a ‘stack’ instead of in the original position, things may have been different.

Doug.

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Shu
Posted (edited)
On 6/16/2022 at 1:50 AM, Bill D said:

Are the valves adjusted correctly?  Is a valve sticking when hot?  Does it loose compression until it cools down.

Also, do you have the thick plastic spacer/gasket between the carb and the block?  If not that could be causing a vapor lock issue if the carb gets too hot.

do you have the part number for the thick plastic spacer under the carb?  

Edited by Shu

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Bill D
Posted (edited)
On 6/21/2022 at 1:09 PM, Shu said:

do you have the part number for the thick plastic spacer under the carb?  

47-049-01-S.  Sorry for the late response.

Edited by Bill D

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