Runs, then dies.

[mblair441]

I have a John Deere 318. If I prime it, it will run for a couple of minutes and then die. I have cleared all the fuel lines, replaced the fuel pump. (it does pump fuel). The old one in fact, probably was not bad, but I broke it while taking it out put in the new one and I cannot reinstall it. I installed a fresh fuel filter between the pump and the carburetor, which is the way it was before when it ran fine. When it finally dies, the fuel filter does seem to be dry. I have inspected the vacuum line between the crank case and the fuel pump. (it’s good). I have replaced both the main and reserve fuel tank pick ups. There is gas in the tank, although it is not full. It is an Onan P engine. I have not gone into the carburetor because when it does get fuel, it runs great. I am out of things to check or try. Any ideas on what could be going on before I haul it to the dealership and pay them $185 an hour to fix it?

 

[beenthere]

Just a thought, but have you tried without the fuel filter in the line? Flow only goes one way.

Another thought, trying to keep it running without the fuel cap. Idea that it is not venting.

Another, new fuel lines. Ethanol can be hard on them, and cause internal breakdown and plugging.

Might try a separate fuel source, connected directly to the carb with free gravity flow.

Just some ideas, if not already covered.

 

[ultrarunner]

Fuel Cap acted the exact same way and baffled many…

The vent was plugged.

 

[thepumpguysc]

If u have the push on filter, the one that fits between the lines..??
Take it off and blow thru it..
I had the same problem..
I put the new one on, the same way as the old one..
It was made “backwards”..!!

 

[mblair441]

Thanks guys. I know that the fuel lines are good and that with the gravity feed it would keep running. But, I will try the fuel cap suggestion since I have been running it with the fuel cap in place. And, although the fuel filter is installed in the correct direction, Occam‘s razor comes in to play.

 

[Quaffer]

Fuel cap and test run without a filter are both easy to try, and better than $185 per hour for tech to look at it!

 

[mblair441]

Well, it wasn’t the gas cap or the fuel filter. It still runs for a couple of minutes and then dies like it is fuel starved. It’s been damn hot down here for the last few weeks, well over 100°. Could this thing possibly be vapor locking?

 

[Richard001]

Well, it wasn’t the gas cap or the fuel filter. It still runs for a couple of minutes and then dies like it is fuel starved. It’s been damn hot down here for the last few weeks, well over 100°. Could this thing possibly be vapor locking?

i don't know, but you said that it ran when using a gravity fuel supply. How long did you run it with the gravity fuel supply ? Long enough to get the engine hot ?

Richard

 

[mblair441]

I did not run with gravity feed for more than a couple of minutes, but will try that again with a sustained feed to see if it is a fuel supply or maybe a carburetor problem

 

[rScotty]

I did not run with gravity feed for more than a couple of minutes, but will try that again with a sustained feed to see if it is a fuel supply or maybe a carburetor problem

Good idea. But I would bet on the vacuum lines that run and feed the fuel pump. They commonly leak air in a way you cannot see by inspecting them. Replace both lines.