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Detroit 2-71 fuel issue.

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berks315

New member
Hello,
I have 2-71 on 20 kw generator. Sat for years, but protected from elements in heated tugboat engine room. It has mechanical governor with off idle, and run knob
After installing a new fuel pump it ran at idle for about 30 minutes. Turned the knob to run. RPM ramped up and after about 5 minutes it died. Would restart but died every time. Few weeks later after getting new fuel line from pump to filter. It will start but only run lower than idle speed for 10 seconds then stop.
 
Hi,

It sounds like it might be sucking in air.

The BEST way to prove that is with a "fuel spill back" test.

You would need to disconnect the fuel return line at a point AFTER the RESTRICTED FITTING and then submerge the line in a partial bucket of fuel.

It might be necessary to make a crude adapter hose to attach to the end of the return line to make testing easier.

Any entrained air will be easily seen as bubbles in the bucket when the engine is running.

If it's sucking air, you need to find out where.

Look ONLY on the suction side of the pump. A leak on the pump's delivery side will result in fuel leaking but NOT sucking air. So, don't waste your time examining the delivery lines or secondary filter.

As a shortcut, I always just suspect the primary (suction) fuel filter(s)....especially if recently replaced.

Gaskets on can and cartridge types get missed and not removed during the service. That won't allow the cannister to seat properly.

The first tool I was ever required to get was a "snot picker" (cotter pin removal tool) for "sweeping" the gasket recesses on fuel filter adapters.

Spin-on gaskets get missed too but, most of the time, the tech doesn't use grease on the seal area and the gasket catches and "bunches up" during tightening.

Grease on the cannister type gaskets helps too and it's good practice to pay very close attention when putting them back on. I used to sort of wiggle and jiggle them while tightening the mounting bolt. Those bolts have gaskets too and will leak air in the head area as well.


New spin-ons can also come with a pinhole in the housing from poor handling sometimes.

That's my best guess anyway.

Good luck.
 
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