The injector pump loses prime after 8 hours

[geocash2]

I have a Northern Lights generator 843n with a Shibaura 3-cylinder motor. Getting the motor to start after it's been sitting for more than 8 hours requires a lot of cranking or opening the bleed screw at the fuel intake hose and priming.

1) Could this be a faulty injector pump, or should I be looking at something else, like the injectors

2) Is there a way to test the pump installed?

3) Can these pumps be rebuilt?

 

[RjCorazza]

No idea about your particular engine or injector pump, but have you confirmed no air leaks from the tank to the pump? A small pinhole or crack in a fuel line, or a filter sucking air can cause those symptoms.

 

[geocash2]

Yes, I have replaced everything from the tank dip tube to the injector pump. After priming, the motor runs flawlessly for hours.

I posted it on this forum because the Shibaura motor is standard on several tractors.

 

[RjCorazza]

I see. There are a couple of injector pump experts here on TBN that will hopefully come in with an opinion.

 

[dieselscout80]

I’m guessing you have an air leak in your fuel supply system between the pickup in the tank and the fuel injection pump.

The leak allows the fuel to drain back into the tank.

 

[lens12]

Leak in supply side would be most obvious cause. Pressurize the tank & look for leaks. I don't think it would be injectors. If you need the pump rebuilt, we can rebuild it a little more reasonable than most shops.

 

[thepumpguysc]

I agree with the leak..
Does your engine have a supply/lift pump.?? If yes the valves might be stuck open allowing the fuel to drain back..??
If u can’t figure it out, they sell a 1 way check valve with push on connectors (cheap) in various size push ends, to fit your line size..
You could replace the black rubber lines with CLEAR lines to SEE where it’s leaking back at..
Good luck