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Discussion Starter #1
The fellow down the road that has the bandsaw mill has been having problems with his engine. According to him its leaking fuel into the crankcase and diluting his oil...He is an old fellow, pretty well set in his ways, and not much in tune with more current engines etc.///////neither am I anymore for that matter, however I do have some thoughts..

The engine is a relatively new Kohler 16 hp 2 cylinder overhead valve and has a fixed jet carb..no external adjustments on carb PERIOD!

The carb is fed fuel via a mechanically operated fuel pump located on one of the valve covers, and is driven by that cylinders camshaft. Origianlly he had thought his problem was the carb, so he ordered a rebuild kit......hardly had any parts in it, and it did not make a difference. I have also torn down this carb and found nothing wrong......Now he is zeroed in on the fuel pump assembly, thinking it may be leaking fuel into the rocker arm / camshaft area and getting into his oil from there. He failed at finding a new fuel pump without buying the entire valve cover assembly (big money) and has been told the pump is no longer available as they were problems..........yet not aftermarket or factory fix exists except buying a new valve cover with installed pump which has same exact numbers on it sa original does, so nothing has really been changed here........

I pulled the fuel pump apart, no dirt no abnormal things found, reassembled it, and used the pumps lever that rides on the Cam to manually work it, and got it to pressurize a low pressure gauge I hooked up to it, and it held this pressure until I released it a long while after. I then hooked up a vac gauge and did the same, and it showed no signs of a leak either, so I am confident this fuel pump is 100% fine.......

My thought is since this engine has fixed jets, made to be emission compliant, it does run richer than one with an adjujstable carb would. I have seen no other motors that run clean or light brown out of their exhausts anymore since going EPA compliant....all of them seem to run a bit on the rich side.......His motor runs fine, does not load up or miss, and his oil level does not increase, and he swears he is smelling gas in his oil.........I can faintly smell gas sort of, but it also smells just like my JD and my other engines oils do, all with fixed jet carbs.

So is there anything else I may have missed, or is he just trying to achieve something by imagining this oil dilution, based on yesteryears engines? The spark plug burns with a dark brown color and IMHO is just fine. he is afraid to use this engine until he "solves and fixes" this oil dilution. Heck we got lots of logs to make into lumber and personally I think the motor is fine.......so what do you think?
 

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EX Super Mod
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Only thing i can think of is the float not closing it off. Maybe the float out of adjustment.:confused:
 

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Discussion Starter #3
Originally posted by jodyand
Only thing i can think of is the float not closing it off. Maybe the float out of adjustment.:confused:
No, float is fine, its set as per tech manual, new inlet valve etc installed, and it shuts off fuel flow. No liquid sloshing around in it either.

Even that anti backfire solenoid is working like it should ..........I just have a feeling its normal for the design of this engine and its carb..........
 

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Tractor Lover
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Drain some of the oil out in front of him and put a match to it...if it ignites instantly there is credence in his theory..if it doesn't, maybe you can get on to cutting wood.
 

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Sounds to me like it's probably ok. The only other thing I could think of to check is the vent on the fuel tank. If something is wrong there and it sits in the sun, I guess it could build enough pressure to push by the needle. I doubt that's it but like I say, it's all I can come up with.
 

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The old guy is exactly right.

The fuel pump is leaking INSIDE the valve cover as engine is running. The happened on a group of those pumps about 2~3 years ago.
Kohler released an upgraded pump a long time ago under a part number that supercedes the old one (yes its built into the valve cover) if he is original purchaser and engine is less than 2 years old its a warranty item. This pump is used today on many applications.
Whoever told you otherwise doesn't know their kOhlers.
 

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Discussion Starter #7
I can see the pump leaking and adding fuel to the oil, but this pump holds vac and pressure all day long, without any signs of a leak. Of course it could leak when its hot and up to temp and operating..........
 

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Take my word for it....they leak.
Old KOhler fuel pump kit number 24 393 14,then went to 24 559 03-S.now the newest number (about the last year) is
24 559 05. Kohlers list $60.28. IM me if you need one , as we give a discount to forum members.
We have the kit in stock. It has always stopped any leak problems.
 
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