On 15 Sep 2006 18:46:54 -0700, "kohler gen" wrote:

I bought a boat with a 1975 Kohler Generator with 275 hrs on it model
7.5A23 (7.5KW), 62.5 Amp 120V, 60 cyc. After I start thje gen, it runs
for 20 Min. producing only 85 Volts (on a load of only 4 lamps 60 W
each). Then after 20 min. the voltage drops down to 50V and gets even
lower. When I checked the spark plugs, two of them were fouled with a
lot of carbon deposite. I cleaned them and restarted the generator and
it did the same, but another two cylinders sparks were fouled with
carbon deposite. Is this due to: 1) too rich of fuel, or 2)a cold
spark plug (Champion J8C), or both? Could it be the rings or valves
problem?
There is also substantial carbon deposite on the cylinder head, is
there a solvant that one can use to loosen this carbon without hurting
the metal??

1) Do a compression test on each cylinder. Then you'll know something
about the ring and valve seals.

2) Try spraying a fine water spray in the throat while the engine is
revving well. This can clean off carbon. But oil or gas fouling
is not a great sign.

Brian Whatcott Altus OK