"Daniel" wrote in message
...

"Bill McKee" wrote in message
k.net...

"D" wrote in message
news
I have a 1992 boat with twin VP 431 DPs. The boat has about 500 hours on
it. It has a San Juan Eng. FWC
half system and the cabin heater is run on starbord engine. It started
running a bit hot on that side. Back-flushed the raw water intake,
good. Replaced raw water impeller--was not real bad, no missing pieces
anyway, pump looks good. Still same problem, heats under load, cools
back down at low RRM. Changed thermostat, no change. Engine pump seems
fine, heater works, no weeping. Am thinking a restriction in the "out"
side of raw water--manifolds maybe.

Anybody have a suggestion on anything else to check?

Thanks, Dan


Pull the end cap on the heat exchanger and see if any garbage blocking
tubes.

That would be something to check. Had not done so as I only put the FWC
on three years ago and do have good water circulation through the cabin
heater. Guess I better check that too! Thanks, Dan


The crap gets stuck in the raw water side. my river jet boat even with a
sand trap, will get small pebbles in there at times.