Need help troubleshooting

arch252 · Oct 3, 2017

I have an LX279 with a twin cylinder water cooled 17 hp Kawi. Model FD501V. I can can cut initially for about 15 minutes and then it stalls, sounds as if it's starved for fuel. It won't restart for a few minutes. The longer you let it sit, the longer it will run before it stalls again so it seems like it's just feeding off what's in the bowl. I have replaced the fuel filter. The fuel lines are in good condition with no blockage. I found that the fuel solenoid had gone bad so I've cut off the plunger and put it back on until the new one gets here.

When it stalls there is still fuel full in the filter. I've pinched the fuel line between the fuel pump and carb after it stalls and opened the bowl drain screw and there is still a small amount of fuel still in the bowl.

The carb was recently cleaned and when it's running it runs great. It doesn't run rough before it stalls, it just shuts down as if the fuel has been cut off. Air filter is nice and clean. Spark plugs in great condition.

Does this sound like the fuel pump needs to be replaced? Anything else it could be?

Ronno6 · Oct 3, 2017

A small amount of fuel in the bowl tends to indicate that the engine is starving for gas..
If the fuel filter is plugged, there would be fuel visible, just that it is not getting thru the element.
Sounds like the filter is plugged. The engine will run until the contaminates in the filter plug up the element,
then settle back out temporarily when the fuel pressure subsides after the engine quits ( no gas being pumped.)
I used to have that problem on a 1965 Corvair with a rusty gas tank.....

bertsmobile1 · Oct 3, 2017

Add to what Ronno posted, debris in the fuel tank will do the same thing.
SO if changing the filter does not get you out of the poo, mow till it stops then quickly pull the fuel line and blow back into the tank.
If it fires up and runs like it had been standing for a long time then the tank is the guilty culprit.
There is also a vent, either in the cap or a small charcoal canister and that blocking prevents air getting into the tank and again stops the fuel flow.

arch252 · Oct 3, 2017

I replaced the fuel filter and I've checked the gas cap vent when I first tried to diagnose it, no change. I checked the tank for debris as best I could, it a JD with the offset tank neck so you can't look straight to the bottom. I shined a flashlight through the bottom of the white plastic tank and it looked fine. When I got this mower 2 years ago I removed the floorpan, removed the tank and cleaned it because I was replacing the fuel lines and fuel tank grommet, so all that should still be fine.

Thoughts on the fuel pump? Could it be restricted and not pumping enough to keep up?

Honda Tech · Oct 3, 2017

arch252 said:
I have an LX279 with a twin cylinder water cooled 17 hp Kawi. Model FD501V. I can can cut initially for about 15 minutes and then it stalls, sounds as if it's starved for fuel. It won't restart for a few minutes. The longer you let it sit, the longer it will run before it stalls again so it seems like it's just feeding off what's in the bowl. I have replaced the fuel filter. The fuel lines are in good condition with no blockage. I found that the fuel solenoid had gone bad so I've cut off the plunger and put it back on until the new one gets here.

When it stalls there is still fuel full in the filter. I've pinched the fuel line between the fuel pump and carb after it stalls and opened the bowl drain screw and there is still a small amount of fuel still in the bowl.

The carb was recently cleaned and when it's running it runs great. It doesn't run rough before it stalls, it just shuts down as if the fuel has been cut off. Air filter is nice and clean. Spark plugs in great condition.

Does this sound like the fuel pump needs to be replaced? Anything else it could be?

It's not your fuel pump or it wouldn't run for 15 minutes. Not sure how old your unit is, but with that engine, it isn't a spring chicken. #1 - The fuel tank should be vented through the fuel cap. Try running it with the cap loose. If it solves the problem, replace fuel cap. #2 - Fuel hose is deteriorating from the inside, creating a flow restriction. This can be tested by removing the fuel cap and checking the free flow of the fuel (into a safe container) by removing the fuel line just before the fuel pump. If you have a steady flow with no loss, no problem. If it starts strong and ends in a trickle, replace old fuel lines.

Good Luck!

arch252 · Oct 3, 2017

Replaced the fuel lines all the way to the tank 2 years ago.

I've checked the fuel cap vent

arch252 · Oct 4, 2017

Well this makes no sense.

So that last thing I had done was cut the needle off the faulty fuel solenoid. I got the new one in and put it on then started it up so I could run it a few minutes and troubleshoot it when it shut off. I ran it for an hour straight with no problem. The new fuel solenoid should not have made any difference. I'm going to run it again for a while tomorow when I have more time and see where I'm at.

Honda Tech · Oct 5, 2017

arch252 said:
Well this makes no sense.

So that last thing I had done was cut the needle off the faulty fuel solenoid. I got the new one in and put it on then started it up so I could run it a few minutes and troubleshoot it when it shut off. I ran it for an hour straight with no problem. The new fuel solenoid should not have made any difference. I'm going to run it again for a while tomorow when I have more time and see where I'm at.

I agree. It doesn't make any sense, but it seems to be working now. Good luck!

arch252 · Oct 5, 2017

Ran it for another hour this afternoon with no problems. It's great that it's not shutting down anymore but if it's not shutting down I can't trroubleshoot to figure out what was causing it.

At this point I think it's either debris in the tank or fuel pump getting picked up intermittently and causing blockage or the coil is going bad. If it acts up again I'll resurrect this thread and update

Need help troubleshooting

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arch252

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bertsmobile1

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arch252

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