I'd honestly say beware of a used genny with way-low hours. Gensets are intended to run, and they don't wear out and die easily. They're meant to keep going on basic maintenance -- oil, filters and plugs mostly. At longer intervals, the brushes should be changed out. Letting the genny sit allows moisture to creep into the windings, the oil degrades, the fuel can varnish, and anything rubber can dry out and rot. Running it circulates the oil and builds heat which will drive out moisture, and keeps the fuel system healthy.
Our '92 Winnie came to us used, with just under 100 hours on the genny. It's a Kohler Confidant V model, old and no longer made, but a good design. It started up and ran OK, so that was acceptable on the purchase inspection; I assumed it would need some maintenance to get it up to snuff. Initial running showed its output voltage was high -- approaching 140 volts under no load. With a load, it settled down to 120 or so. Figured it would need to run a while to get the crud out of the carb and governor, so the policy initially was to fire it up with everything turned off, hit the roof air conditioner to pull the voltage down and then turn other things on. After a bit, I noticed the governor tended to hunt a bit to much, causing the voltage and frequency to vary too much. I wasn't surprised, really, so before the first longer trip of the year, it would be time to get the little beast put right.
That's where it got interesting...
Got it started and warmed up, governor started hunting consistently, so it was time to shut it down and take the panel off to get to the governor adjustments, also back off the elctric choke a bit because it was definitely over-choking even in the cold, and might be holding the choke a bit, adding to the hunting effect. The choke adjusts like the same kind on a car -- loosen the plastic housing with a couple of screws and twist the plastic housing slightly in the direction of the "lean" arrow. Only do a bit at a time, and tighten the clamp screws back up. Got the panel off to access the governor adjustments. Hit the starter button aaaaand... Cranking, cranking, cough no start. Try again. Same thing. Third try, Nothing. No crank, now. What the heck? There's no interlock to fight with, so what's up?
Check fuses -- Whoops! Somebody had done a Bad Thing. The starter fuse was blown, but wrapped in tinfoil as a quick fix. The tinfoil was coming apart, so no power to the starter. Closer inspection showed this was the result of mixing up the fuses. The 5 amp controls fuse was put in the starter fuse position by mistake and had obviously blown. The 15 amp fuse was in the controls position.
These are somewhat hard-to find ceramic type "ABC" fuses. Best course of action is to locate some new fuses (even for the one that tested good, because vibration and age takes its toll...) and a new fuel filter since the old one looked suspiciously like the original. DW tracked down the parts the next day while I was at work.
Put in the fuses and the fuel filter. Hit the starter...cranked...cranked...cranked... no start. Poked around, found one of the wires for the remote starte controls broken off at the pin in a plastic connector. Shoudn't make a difference, but stranger things can happen. Next day's task is finding Molex connector pins.
Got the pin, crimped it on and got it back in the connector. Starter cranks, still no joy.
Looks like a fuel problem now. Had a conversation with a generator service tech, got the lowdown on how to safely jumper 12 volts to the fuel pump and the shutoff solenoid on the carburetor... Both are working. Maybe the pump is weak?
Decided to poke around some more, prepared to take the choke assembly off to get to the carb and fuel lines. Pulled the plastic cover off the choke actuator coil, and the paper gasket fell out -- which was mis-sharpen. Hmmm... Hit the starter again. Crank... Cough... Crank... Fired off and ran!
Turns out the paper gasket for the choke housing was making the choke stick. Generator tech says it's not even needed if the housing tightens down without it, which it does.
So... With the choke working correctly, I could get the genny warmed up. Tweaked the regulator output down to a safe 129-130 volts with no load,and balanced the altitude screw and the electronic governor gain to tune out the hunting action. Now it purrs along and keeps a steady 120 volts even with the roof AC on.
Most everything I corrected would have been caught long ago if the genny had been used and maintained regularly. Letting it sit in order to avoid the little extra maintenance just adds up to bigger hassles.
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