Kohler Back fire

[Louis]

So I have kohler 22hp that will back fire when I turn it off or let the fuel pmup run to much before I start it.
Ignition is grounded
There is no fuel pump on the valve cover
Fuel prssure is around 5psi

I was told that some older kohlers had a vacuum fuel pump that helped regulate the fuel. This motor was off a old steamway so I have no clue of it's age and the spec # is gone.

I am thinking of putting a switch to turn off the fuel pump before I turn off the key.

Thank You.

 

[frank]

Louis
surtec in Tracy are experts in those motors and price wise are reasonable.
on MacArthur in tracy

frank.

 

[Shane T]

I have an old Kohler with a fuel pump switch. I will turn of the pump and let it idle for a minute before I turn off the ignition. If you switch the pump be aware that it is easy to forget and leave the ignition switch on after the engine has died. It will likely fix the back fire problem. An on off valve would also work.

 

[bob vawter]

i betcha a lawn mower shop could hep ya out wit that.................!

 

[Connor]

i betcha a lawn mower shop could hep ya out wit that.................!

Bawb, if you're not going to help, shut up.

 

[bob vawter]

LOOK HERE...i don know WTF ur'r trying ta kid........
but #1 i jus talked to the real connOr.....and he laughed so hard........

well anyway.....i tried to talk him into a cameo anyway!

he sED maybe sometime....and we made up a secret codeword so only I would know it was him........
believe me the REAL connOr thinks yous ALL are jerks........

an' 'cides a lawn mower shop would be a LOT cheeper than a TM distributor.........

 

[steve_64]

an' 'cides a lawn mower shop would be a LOT cheeper than a TM distributor.........

and probably have a LOT more experience with them.

 

[Louis]

I went to autozone and got a switch. Turn off the fuel pump about a minute before I turn off machine and no backfire.

 

[bob vawter]

most likely you have a carbon buildup........stays hot for a few seconds after shutoff and will detonate any gas that comes in the combustion chamber......at least that happens to my Case lawnmower with the Kohler....sometime ....until i started using premium gas.....

 

[Louis]

Can you run fuel cleaners in the kohler and not screw anything up. It still back fired after it was almost out of gas. Ichecket the fuel solnoid and it is working. Now I just turn down the machine and turn off the fuel pump and let it run out of gas.

 

[Shane T]

It's probably as Bawb says. Carbon build up in the combustion chamber. It's not that difficult to pull the heads and de-carbon it, especially if its air cooled. Just get a couple head gaskets. I believe its suggested periodic maintenance anyway.

 

[bob vawter]

you mean ....
i was RIGHT?

 

[KevinD]

Your owner's manual should list the proper shutdown procedures to avoid this occurrence. If your engine is equipped with a fuel shut-off solenoid, Kohler recommends that the throttle be set between half and full throttle before turning the key switch to OFF.

 

[bob vawter]

yep...that's the real reason.....you GOT ta throttle down before you turn the key off......
burn premium gas also.........

 

[KevinD]

If non of the above helps.

Throttle it down to a idle.

Let it cool a minute or 2.

Close the choke as you turn off the key.

If it doesn't get air it can't burn anything.

 

[GCCLee]

Ker POW, hey atleast your margin of getting mugged slims down.Glad ya got it fixeredChris

 

[Louis]

I let it cool down every time and turn off fuel pump about a minute before I turn it off and do the choke at the same time,
I was told I need to get the vacuum fuel pump put on to help cut off the fuel. It has the holes to mount it.

I was also told to take the carbon off the piston to put 2oz of water slowly in the carb while it's running and hot and this would clean the pistons.

 

[dealtimeman]

I think your fuel shut off solenoid is either dirty or just not working. I would remove and test for proper function.

 

[Mikey P]

My 30hp Kohler farts as well if I don't give it about two minutes of cooling down time.

What's the big deal? Can damage occur if it back fires too often?

 

[bob vawter]

My 30hp Kohler farts as well if I don't give it about two minutes of cooling down time.

What's the big deal? Can damage occur if it back fires too often?

DEPENDS......if it's backfirin' out the exhaust...prolly won't..
if it's backfirin' out the carb...yor screwed!
best to use premium gas to clean the carbon deposit PLUS you can add a dribble of lead additive to the gas....

 

[GCCLee]

My 30hp Kohler farts as well if I don't give it about two minutes of cooling down time.

What's the big deal? Can damage occur if it back fires too often?

If I wasn't so new I would run off a cliff with this one Mikey !!!

 

[steve_64]

if you want to permanately eliminate the problem stop using gas with ethenol. thats what causes the carbon problem.try a tank of it and i bet the problem goes away. that goes for most emission problems with cars too.

 

[steve_64]

My 30hp Kohler farts as well if I don't give it about two minutes of cooling down time.

What's the big deal? Can damage occur if it back fires too often?

you create a hot spot on the piston head that keeps weekening until the pressure between the valve and piston head blow a hole in it.

 

[Louis]

I pulled and tested the fuel shut off solenoid. I got it down to a small pop. It has done it so loud that it bent the flex straight and I couldn't hear anything but ringing for 20 minutes. Ithink I will run some seafoam in it and then try the lead additive. I am still going to put the vacuum pump on it and see what that does.

 

[Louis]

Well I put new cylinder heads on new fuel shut off solenoid and it still backfires. So what is next ? I'm at a loss. It's embarrassing at a customers house.

 

[Shane T]

So what was the condition of the head and piston tops and cylinder walls when you had it apart? Do you have any exhaust leaks, particularly between the manifold and head?

 

[Louis]

#2 had a crack between the valves. A little carbon build up. Pistons looked ok.

 

[steve_64]

have you tried gas without ethenol?

an old timer told me about this about 20 years ago and as long as ive done it ive never had the problem with any motor. before that i experienced it with several motors.

 

[steve_64]

DEPENDS......if it's backfirin' out the exhaust...prolly won't..
if it's backfirin' out the carb...yor screwed!
best to use premium gas to clean the carbon deposit PLUS you can add a dribble of lead additive to the gas....

premium gas or higher octane isnt good for small motors ive been told. it alters the timing or the gas will combust too early before the spark due to the heat build up upon pressure on the compression stroke resulting in premature wear of the crank bearings and such. they are still pushing when they should be releasing and it can cause the piston arm to break too and in extreme cases break the crank.

 

[MattLimbach]

We unhook our vacuum hose first,to reduce the load on the engine,then we shut the engine down at approx 2500 rpms, otherwise we will get back-fire on our 27hp kohler.
I think that repeated back-fire could potentially damage the engine. Also, our engine is direct coupled, and I think it can cause damage to the coupler.
Where we are, ethanol-free gas is not an option.