Kohler CH22 starving for gas

[Robert Boudreau]

I have owned this 62" mower for 20 years. Suddenly, the fuel filter is empty and the mower shuts down - as if I turned the key off. Let it set and the fuel filter {Vacuum} refills to 50 to 75% with the mower off. Restart and it may run for 30 minutes or 2 or 3 hours (it decides). Here is what I have done: Replaced fuel pump (twice), replaced fuel filter, replaced all fuel lines including the rubber grommets on each saddle tank (the pick up hose in the tanks are new), blew out the 90 degree elbows on each tank, new tank selector switch, new breather valve (flapper) & gasket, rebuilt carb and new gaskets, verified governor settings, gas tank cap vents are clear, tanks are clean, new spark plugs, new coils and the compression test were 123 & 125 PSI. I don't think I left anything out. Mower starts great. It mows great (62" deck). You start mowing with a fuel filter 50 to 75% full. 15 minutes later, you see NO visible gas in the filter.....after which it will shut down at any time. It may last 15 minutes....1 hour or 2 to 3 hours. My yard takes 5.5 hours to complete under normal conditions. What am I missing??? I have re-inspected all the new fuel lines, been through 2 new fuel pumps, rechecked the gaskets on the manifold and carb, re-inspected the rebuilt carb, fittings are tight, hoses were new and feel snug. Any suggestions?

 

[Scrubcadet10]

What fuel filter are you using? And how did you verify the vents are working properly?

 

[Robert Boudreau]

What fuel filter are you using? And how did you verify the vents are working properly?

The filter was purchased at our areas go-to equipment dealer. I don't recall the exact make. I used a wire and air hose to verify the vent holes were open. I have also loosened the tank cap, as I was mowing, to see if it would increase the gas flow in the filter - which it did not.

 

[ILENGINE]

Shuts down as if you turn off the key doesn't sound like fuel issue to me. Loss of fuel issue normally will spit and sputter a few seconds before actually dying. Issue to me thinks more of a loss of spark issue. Does this engine have the oil pressure switch which could be faulting out and causing the engine to shutdown.

Compression is below the 160 minimum that Kohler suggest, which may not be a cause but could be a symptom of something else.

 

[Robert Boudreau]

Shuts down as if you turn off the key doesn't sound like fuel issue to me. Loss of fuel issue normally will spit and sputter a few seconds before actually dying. Issue to me thinks more of a loss of spark issue. Does this engine have the oil pressure switch which could be faulting out and causing the engine to shutdown.

Compression is below the 160 minimum that Kohler suggest, which may not be a cause but could be a symptom of something else.

I will have to see if it has an "oil pressure switch"? The shutdown takes about 3 seconds...a single or duel very quick shudder then nothing. But, I am drawn back to the empty fuel filter - 15 minutes of sitting and I have enough gas in the filter to restart. Would the oil pressure switch impact fuel delivery? Fir the record, I have noted that the lipstick tube is loose and easily pulls out from the block if you lift it. Would that impact the vacuum that operates the fuel pump??

 

[slomo]

been through 2 new fuel pumps

Where did you get these from? Scamazon or Fleabay? OEM parts????

 

[Robert Boudreau]

From a reputable mower/tractor/small equipment dealer.

 

[slomo]

Rig up an aux fuel tank that is HIGHER than the carb. Just to confirm lack of fuel is the issue. Mow with it a while. Many a time fuel filters can look dry and the engine still runs.

re-inspected the rebuilt carb

Did you pressure test the carb needle/seat at 7psi for 30 minutes? Does the needle allow fuel into the bowl area?

 

[slomo]

From a reputable mower/tractor/small equipment dealer.

So the new fuel pumps are not working? Guessing these are OEM Kohler parts?

 

[Robert Boudreau]

I removed the fuel line going to the carb and placed it in a container. I then turned the key. The pump was pumping gas thru the line into the container. So, the pump is working.