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From: Steve Weinstein (no email)
Date: Wed Jan 05 2005 - 23:58:28 EST
Jim, although checking or replacing is a good idea I would think that an impellor missing a vane (tooth) is most likely the culprit, especially if the overheat situation kicks in at medium to higher rpms. At higher rpms the fan belt is driving the water pump at a higher rpm to circulate the water faster. If your impellor is missing a vane then I'd think that your cooling water circulation was below specs and that could cause an overheat problem.
Just my $.02.
Steve Weinstein
s/v HYDRO-THERAPY
1981 Cherubini Designed H33
Sailing out of Oyster Bay, NY
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----- Original Message -----
From: Jim Sims
To:
Sent: Wednesday, January 05, 2005 7:50 PM
Subject: lv-ab: Perkins 4-108 overheating problems
I have a 1973 Gulfstar 41' ketch sailboat with a Perkins 4-108. It is
overheating at medium or higher rpm. The engine was rebuilt
(allegedly)about a year ago, just before i bought it. It was not really
used last year [due to boat repairs keeping it dockside] except being
turned over at the dock ~monthly.
I removed the raw water thruhull and it has great flow. I removed and
cleaned the raw water strainer (not even slightly clogged). I removed the
raw water to exhaust hole and back-flushed all the way through the raw
water strainer (last item before the thruhull - flow is great. I removed
the raw water impeller cover and it seems fine though it has shed one
rubber? 'tooth' - i will be replacing it.
I opened the end of the heat exchanger (and located that missing impeller
vane) - it didnt seem to have scale in there, but i didnt see any
(obvious) sacrificial zincs.
I suspect the thermostat has just enough scale to keep it closed, but cant
locate it on this engine (though i found the one on my neighbor's 4-254
easily). Can you tell me where the thermostat is located? And those
sacrifical zincs?
thanks!
jim
living aboard Nekkid Joy
1973 GS 41
lying Charleston, SC - relocating to Melbourne, FL
www.nekkidjoy.com
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