Kohler CH20 Floods even with new Carb

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Byrd

Forum Newbie
I just purchased my 3rd Walker. It's a 2004 with low hrs. It has the Kohler CH20 64694. My problem is, after a couple minutes of running it begins to flood. Blows gas smoke and starts to skip. I replaced the Keihin carburetor with a new one but it did not help. The engine has the factory mechanical fuel pump which seems to operate fine. I replaced the fuel lines and filter. It would seem to be getting more fuel pressure than the float can handle but am I missing something? Your help would be greatly appreciated.
 
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The carbs for mechanical fuel pumps have different floats than the ones for impulse pumps.
Sounds like you got the wrong carb.
 
When you say impulse are you speaking of the fuel pump that is mounted to the valve cover. If so that is what this engine has. I also replaced the carb with the one that replaced the original. Is there an electric fuel pump that would work?
 
He said that it is blowing blue smoke which would be oil burning not gas which would be black. I would start looking into why he is burning oil. Bad breather, Oil in the gas, bad rings, blown head gasket.
 
Yes ILENGINE is right with the color of the smoke, its oil. You do have a mechanical fuel pump and it sound like its working just fine. Some things I don't agree with and the different floats for different fuel pumps is one of them, never heard of such a thing :confused2:
 
reynoldston said:
Yes ILENGINE is right with the color of the smoke, its oil. You do have a mechanical fuel pump and it sound like its working just fine. Some things I don't agree with and the different floats for different fuel pumps is one of them, never heard of such a thing :confused2:
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Sorry for the confusion, the smoke is definitely from gas - not oil. I have ordered an electric fuel pump [1 - 4 psi] and a fuel pressure regulator. I can't return the carburetor for refund and another is over $300. The rebuild parts for this carburetor are few and expensive, I don't see a new float available. I have thought about going to fuel injection.
 
Byrd said:
Sorry for the confusion, the smoke is definitely from gas - not oil. I have ordered an electric fuel pump [1 - 4 psi] and a fuel pressure regulator. I can't return the carburetor for refund and another is over $300. The rebuild parts for this carburetor are few and expensive, I don't see a new float available. I have thought about going to fuel injection.
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How in the world can you buy the float story? The float regulates the gas level inside the carburetor and has nothing at all to do with fuel pump pressure. Don't know what different a electric pump is going to do? Did you test the pressure on your mechanical fuel pump? If anything you have more of a needle valve problem or a wrong float level.
 
reynoldston said:
How in the world can you buy the float story? The float regulates the gas level inside the carburetor and has nothing at all to do with fuel pump pressure. Don't know what different a electric pump is going to do? Did you test the pressure on your mechanical fuel pump? If anything you have more of a needle valve problem or a wrong float level.
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UPDATE....The Walker is fixed and running great. The problem was in the fuel pump. The factory fuel pump is mounted on top of the left valve cover. The pump is operated by the movement of the rocker arm inside the cover. The problem was that the fuel pump diaphragm had a hole and was leaking fuel on top of the head which ends up in the crank case. Thankfully I did not run the engine very long and there was no damage done to the bearings. New fuel pump / valve cover at $98.00 + tax

Thanks to all for the input
 
Appologies for float it was the wrong word to use.
Mechanical fuel pumps
Impulse fuel pumps
Gravity feed
all supply fuel to the seat at different pressures.
The pressure that the float valve needle exerts upon the float valve seat might not be enough to fully close off the fuel supply when recieving fuel at a higher pressure.
And to obverse, too much seat pressure can cut off the supply too soon resulting in a fuel level too low causing the engine to run lean and even hunt a bit.
I have had this problem a couple of times and it took a looooooooog time to sort out because the engine was fitted with one of the carbs shown as being correct for the engine.
Not being a Briggs expert I always though they were all set up the same, just from different suppliers.
However with the Craftsman the carb fitted was but not for a fuel pump so the thing would randomly run rich, eight stroke a bit then carry on as normal, particularly when the govener allowed the butterfly to go WFO.
But the wrechard thing would not replicate this in the shop yet would regularly do it in the grass
Unbeknown to me the PO had gone to breaker and asked for a carb for a 13 Hp engine because his one had filled with water & corroded beyond use.
In frustrated desperation I changed the carb and the mower ran perfect.
Used the old carb on another engine with gravity feed & it ran perfectly .
Being used to Amal carbs that have random float valve seat heights I made up some float bowls with a nipple in the bottom so I can check the fuel height inside the carbs when I get one in that seems correct but just won't run properly.
It appears Walbros are not much better than the old concentrics.
Where as the Honda carbs are all exactly the same ( well as good as I can measure ) and the makunis fitted to the Vanguards as similarly very consistant
 
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