79 mercruiser 470 temp a little high

b_ry

Cadet
Joined
Aug 29, 2009
Messages
16
i purchased this boat about a month ago and it had been sitting for about a year, first time out it got warm on the return trip about 190, i flushed the antifreeze side out and though i would try again, next day same thing but temp went a little higher. i took it to a shop and they put a new impellar in it,(the old one was fried) and also replaced the thermostat because they said it was in need of one, (they put a 160 degree one in it). today i took it out and on the plane it was runnin about 175 and 160 at slow speeds. i wasnt exactly taking it easy on it, wot most of the time, well i guess my question is, is that to hot? and if so what can i try to bring the temp down a little?
 

TowRoper

Petty Officer 1st Class
Joined
Jul 24, 2009
Messages
302
Re: 79 mercruiser 470 temp a little high

i don't see a problem with your temps its going to go up a little if your running hard. lets see if anyone agrees
 

b_ry

Cadet
Joined
Aug 29, 2009
Messages
16
Re: 79 mercruiser 470 temp a little high

ok i wasnt sure, i thought i might pull the heat exchanger off and clean it up, but maybe i dont need too.
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: 79 mercruiser 470 temp a little high

try actually checking the service manual for operating temps on that motor. you may even be surprised.
 

stonyloam

Vice Admiral
Joined
Mar 13, 2009
Messages
5,827
Re: 79 mercruiser 470 temp a little high

Thanks for the Sunday morning challenge Rodbolt:D. Took a while to find it. You are right it is not what I expected. Hint: It is in the troubleshooting notes in the cooling and exhaust section (the only place I could find it anyway).
 

b_ry

Cadet
Joined
Aug 29, 2009
Messages
16
Re: 79 mercruiser 470 temp a little high

your right it did take a minute to find but the manuel i have says 165 at idle and up to 200 at wot is ok, i was just worried because this is my first 470 and the first couple of trips went bad, thanks guys
 

TowRoper

Petty Officer 1st Class
Joined
Jul 24, 2009
Messages
302
Re: 79 mercruiser 470 temp a little high

your welcome! happy safe boating!
 
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