First, there has been the smell of diesel present under the floorboards whenever it has been run. This started small and grew so gradually that I had been ignoring it. Jane however is the ever-practical one. "Why does the generator smell like diesel?" she asked, pointing out that there was indeed an elephant in the room, and leaving me no more room to pretend that there was nothing amiss.
I searched all the diesel connections and didn't find any leaks. Finally, I put it down to a possible fine mist escaping from a high pressure line feeding one of the injectors - it's hot up there and any leaked diesel would quickly evaporate. Yeah, that's the ticket.
But the smell persisted.
And then the generator began to act like it was starving for fuel. So as an experiment I turned on the electric fuel pump and pressurized the diesel feed line to the generator. It immediately smoothed out and ran normally. No problemo! All I have to do now is run the fuel pump whenever I run the generator. And the bilge blower to get rid of those diesel fumes.
Some of you probably have this figured it out by now...
OK, at this point I have grudgingly admitted that there is something actually wrong. So I took the simplest and cheapest approach as a first step: I changed the generator fuel filter. As a problem-solving method, this is a good first step. It cost very little, was very little effort, and in even the worst possible case, it does no harm.
Unfortunately, it didn't fix the problem.
Putting the new pump in was an even bigger puzzle because the hard line on its discharge must be installed before the pump is placed and it must be threaded thru some obstacles before the pump can be placed into position. And all of this must be done while maintaining the gasket in place (I used Permatex to glue it to the lift pump) and fiddling the mounting bolts into their holes, blind.
Yup, that fixed it. Both problems. Although invisible under the mass of corrosion, apparently the pump casing had corroded thru or cracked, allowing diesel to escape on the pressure stroke and air to be sucked in on the suction stroke.
This was a classic case of following my troubleshooting aphorism:
"Do the simple, lowest cost things first."