Kohler Command stalling / fuel supply problem solved

Yardman999

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  • / Kohler Command stalling / fuel supply problem solved
RE: Kohler CH22, horizontal shaft, 1995 vintage, in my Yardman 999 garden tractor

Over the past couple of years, the engine has been stalling after about 1.5 gallons of gas has been used. From the tank's full-point, this stalling occurred when the fuel level lowered to about the carb's height. The engine would die like it had run out of fuel; refilling the tank to the top, and letting the engine cool for a while would let it restart and run like a champ until the fuel level fell again.

To address this I've replaced the fuel filter a couple of times (read online that they can be picky about the filter), the fuel lines, pulled/inspected/tested the tank's dip-tube, and a long time ago had replaced the fuel pump. No change. After doing some searching here and elsewhere, I ordered a new fuel pump recently. While waiting for it to arrive I read some more on how the fuel pump operates -- this one uses variations in the crankcase's pressure/vacuum to pump the fuel, via a diaphrapm. So I decided to find and replace the crankcase vacuum line (attaches to the crankcase near the output shaft on this CH22), but the original seemed fine; no improvement. So checked the fuel lines conditions/connnections yet again, and in doing so removed the air cleaner's base plate. And ... the cause found ... the thin, black, vinyl-ish PCV hose (that goes through the plate to the carb's inlet) had popped off its nipple on the intake manifold. From the factory, the hose uses a spring clamp there, but that slick hose material, along with the engine's oily-goo from crankcase gases, makes for a very weak hose connection. So I reattached the hose with a fuel line worm clamp instead, and ... problem solved.

So my guess is that the lack of PCV vacuum caused the crankcase to be operating at a higher pressure, thus causing this type of fuel pump to underperform. And now that it has arrived, I have a new fuel pump for the shelf. :-{ (Fortunately it was low cost.)

FYI -- this 1995 CH22 runs like a champ. Doesn't burn oil, starts well, etc. Over the years I've had to replace the ignitions coils to solve a weird problem (in addition to routine spark plugs, oil, filters), but that's all it has really needed. Don't get me talking about the spindles / pivots on the 999's finish-mower deck, though.
 

gainestruk

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  • / Kohler Command stalling / fuel supply problem solved
Great description of how to fix, thanks for info !
 
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