# Kohler CH 20S fuel pump ?



## Gary Alford (Jun 18, 2010)

This motor is in my neighbors 98 legacy, it has been giving us fits ! We removed the fuel tank and cleaned replaced all the fuel hoses cleaned the carb and replaced the carb. Runs good a fuel weeks and starts acting up again. Today the fuel filter looks like it has black junk in it again even though we replaced and cleaned every thing as mentioned. Looks like a small crack in the valve cover where the fuel pump mounts but it isn't leaking oil, was wondering what runs this fuel pump, it is pumping does this pump run on engine pulsations or is it mechanical? what looks like a crack could just be a casting defect of some sort.


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## jhngardner367 (Apr 5, 2011)

It's a vacuum operated pump. It has a hose that runs either to the valve cover,or the crankcase,to supply vacuum pulses to it(#7).
http://www.partstree.com/parts/kohl.../fuel-system-8-24-10-tp-2439-c-rev-10-2-2006/

If the fuel bowl is getting black particles,them the valving inside is crumbling,and the pump should be replaced.You do NOT have to buy one from Simplicity(expensive!),just order one like these:
http://www.jackssmallengines.com/Parts-Lookup/808656/321923/ps?gclid=CI_198Hz1MYCFZKFaQodxaYPzQ
Don't try to usean electric pump,as they put out too much pressure.


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## Gary Alford (Jun 18, 2010)

No this fuel pump mounts directly to the valve cover, has no pulse hose just one hose from the fuel filter and one to the carb.


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## jhngardner367 (Apr 5, 2011)

If you can remove the pump,it will probably have a vacuum passage on the underside,in the form of a reed valve.
This engine series used this type(valve cover mounted) and some used the external 3-fitting type.
The operation principles are the same Vacuum pulses from the engine make the diaphragm pulse,and pump fuel.
In yours,it's possible that a gasket,or seal is crumbling,and getting pushed through the line,to the carb.
Hopefully,this manual will help.

file:///C:/Users/Owner/Downloads/SM_2469006_CH18_thru_CH25_CH620_thru_CH750_REVISED+5_14.pdf


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## Gary Alford (Jun 18, 2010)

Actually we are seeing the crud in the fuel filter, which makes no sense because we flushed the tank and replaced all the rubber hose from the tank to the carb, and we also purchased a used carb on-line that was rebuilt and cleaned ultrasonically. It worked good for two weeks till he removed the deck to replace a spindle bearing. This also has around 1500 hrs on it but has been taken real good care of.


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## Gary Alford (Jun 18, 2010)

So it is possible that if the valve cover is crackled it could be sucking air. He says that the filter looked try sometimes when it quit and loosening the fuel cap made no difference.


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## jhngardner367 (Apr 5, 2011)

Very possible. It could also have a bad reed valve,which would cause a drop in vacuum,so the pump wouldn't work.
The bad thing about the pump being in the valve cover,is the expense. The external pumps are $17 and up,but the type you have runs about 3 or 4 times that at the Simplicity dealer.


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## Gary Alford (Jun 18, 2010)

I think my neighbor is so disgusted with this thing he might buy a new one! we have been messing with it since Spring and he has a lot of grass to mow. It was bought in 98 and he didn't really have any trouble with it till last summer. It also gets expensive once they get this old, usually one thing or another, but it has the striping set up and really mowed nice. I usually just buy the cheap mowers and buy a new one in about 8 yrs. can't afford the $7000.00 a legacy cost.


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## Gary Alford (Jun 18, 2010)

Does anyone know what the fuel pressure should be for this motor? they do sell 2-4 psi. electric pumps on e-bay.


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## jhngardner367 (Apr 5, 2011)

It's usually 1.5 PSI,with some as high as 2.5 .
Electric pumps usually need a pressure regulator,to avoid flooding.


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## Gary Alford (Jun 18, 2010)

*kohler ch 20 S pump*

Thanks for the info, see why a electric pump wouldn't work out.


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