engine symptom/filter issue seemed counter-intuitive to me...

[MikeP]

Thought I'd post this to either be helpful or demonstrate my lack of understanding re filter symptoms...

NL Genny had always started/ran perfectly. Recently it would take 2-3 attempts to start. It would start immediately, run for a few seconds, then stop. After the second/third restart it would run just fine for the duration and under full load.

I assumed it was some sort of air leak that was allowing fuel to drain back or something like that. But, while I was troubleshooting that I decided that since I hadn't replaced the fuel filters in 6 years, that that would be a good thing to do. After installing/priming the new filters I started the genny and it started/ran correctly. I figured that was due to priming the filters so I ran it a while, shut it down, waited a few hours, started it and once again it started/ran correctly. So I waited two days and did and it again started/ran correctly.

So it seems that replacing the filters corrected the problem but that doesn't make any sense to me. It seems to me that if there was a clogged filter issue, the unit would have exhibited the opposite behavior - it may have started OK but not run under load.

I'm a bit vexed though it doesn't really matter since it's running fine. Only thing I can think of that makes any sense is that perhaps the O-ring seal on the Racor primary was leaking a bit but there was no sign of fuel leakage and the o-ring looked ok when removed and there was no trace of fuel anywhere.

 

[Will]

I had an identical starting problem with my generator and eventually discovered it was caused by a small air leak resulting from an impropery tightened clamp on the fuel filter . When shutdown for a while, fuel starting at the filter was syphoning back to the fuel tank.
Will

 

[Avenger]

The start-stall symptom is a result of an air bubble in the fuel system. The engine starts on the fuel that is in the injection pump and then it sucks in the air bubble and stalls. As Will said you probably corrected a small air leak when you changed the filter. The leak wasn't sufficient to affect the operation of the engine while running, but after sitting for a while it accumulated into a bubble sitting at a high point in the system (possibly the filter itself) large enough to cause a problem. Once pushed through it would run unit the next shutdown.

 

[davidwigler]

I changed the original Dahl filter for the generator over to a SeaMax Double Double filter kit and added an inline priming bulb before the filters. Works great.