20 HP COMMAND PRO WON'T START AFTER SITTING 3-4 DAYS

NORMKENN

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Craftsman Lawn Tractor Model No. 917.273480
Kohler Engine Model: CV624-65578 Twin V 20 HP

Engine will not start after sitting for 3-4 days without first introducing propane into the carburetor. Cold engine will start after three or four attempts to crank it for up to about 4 days of sitting, after that, it refuses to start until I feed propane to it. Once it starts the first time, it will fire up immediately on subsequent attempts. After starting, the engine runs great – smooth with good power. It appears to me that the engine is not getting any fuel when it refuses to start. Tractor is approximately 15-years old. Any suggestions would be greatly appreciated.
 

RDA.Lawns

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Ok propane? Why propane? I use a touch of gas . Really doesn't matter it works I guess lol. Now to the problem. Its a fuel issue. Is the choke working? Yes then next step would be is there some obstruction in the fuel line. The pump could be weak without being non functioning. Could also be a little trash in the filter or bottom of the tank. I don't think it'd be a carb issue I'd look at the pump. Maybe someone with more experience can chime in and help more.
 

skippymud

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That is a wild problem. Curious - Had you tried fuel in the carb instead of propane?
 

skippymud

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Fuel filter in backwards?
 

NORMKENN

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Fuel filter in backwards?

It has a new fuel pump and new fuel filter. Fuel filter has an arrow on it indicating fuel flow direction. I use propane because it is the easiest method of getting fuel to the carb - no liquid to spill trying to pour it into a horizontally mounted carburetor. Engine runs fine after initial start, and will re-start without being primed for about 3-4 days after being started with propane. I was just wondering if there is some common problem with the carburetor on these engines? What specifically should I be on the lookout for when rebuilding the carb?
 

bertsmobile1

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A couple of things come to mind.
How is the battery after 3 or 4 days ?
If it runs down a bit you can get to a situation that it is cranking too slow to get enough venturi to draw fuel into the carb from the float bowl.
The float might be set a touch too low and after a couple of days & a little evaporation you get the same situation as above.
As it is an old engine the rings might not be sealing as well as they could so again the same situation as above.
Incorrect valve lash can do funny things to starting.
A sticky fuel solenoid will also exhibit these symptoms.

Bad ground contacts can cause similar symptoms, as will a partially blocked idle circuit.
A sticky float needle can also exhibit these symptoms
And don't forget plain old bad / stale fuel.

I am not a big fan of goos like seafoam but it should shift small amounts of gum in the float valve & idle fuel circuit.

My first test would be to drain the tank & put in some nice fresh fuel from a reliable source.
Toss the old stuff in some ones car.
After that go with the seafoam remembering that it takes quite a bit to run through the system to do any cleaning.
Measure the voltage of the standing engine and the voltage at the fuel solenoid while cranking the engine.
 

NORMKENN

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Finally got around to checking out the no-start after sitting for several days problem. Went on a 2-week vacation and when we got back the engine wouldn't start. Rather than using my usual method of priming with propane, I disconnected the fuel line to the carb, and the fuel pump was working fine. I then removed the anti-backfire solenoid actuated valve from the carb and fuel drained from the bowl. I removed the actuator that is SUPPOSED TO ALLOW FUEL TO FLOW THROUGH THE CARB WHEN THE IGNITION SWITCH IS TURNED ON. I then reinstalled the valve (minus the actuator) and cranked the lawn mower twice to pump fuel back into the carb bowl, and then, on the third crank, the engine started. The battery voltage didn't drop below 11.2 V when cranking, so I don't believe it was a voltage problem. I looked up the specs on the valve several months ago, and If I remember correctly, the valve is supposed to operate properly above 10 V.
 

Fragger

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There you go answered your own question, i was thinking about that as i have cut out both on my scotts and jd !!Good job on trouble shooting guys had some good recommendations :thumbsup::laughing:
 

ILENGINE

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Two things you need to check is are you getting battery voltage to the fuel solenoid in both the crank and run positions. There has been cases where the key switch is either incorrect or had failed and you will loose voltage in the crank position.
 
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