thermostat temp...

[hotmerc]

i have twin 1998 4.3's in my 88' carver santego. since i owned the boat the temp at cruise was around 180 degree's. i had recently replace my risers and manifolds (98 originals!) that were really clogged up. the port engine now runs at 170 degree's, but the starboard still runs at the same temp of 180. the thermostat is a 160 degree stat. i have a buddy with the same engines that runs a cruising temp of 140-150 degrees. i tested the thermostat and it works. is this the proper stat for this motor or can i dorp to a lower temp stat?

 

[bigbrownbuku]

Re: thermostat temp...

find someone with an infrared temp gun before you go any further. if you have a closed cooling system 180 is about normal.

 

[Scaaty]

Re: thermostat temp...

Enclosed system can run 180, 170 OK, but open (raw water cooled) should have 140 stats. You don't say which you have. More info would help. You in salt water? One block might be a little more clogged up. All in all, I wouldn't worry about it

 

[hotmerc]

Re: thermostat temp...

in salt water, raw water cooled, pumped in through the outdrive. thermostat is 160 degree. it does another funny thing. in cruise mode at 3500 rpm, temp will run up to around 180-190 for about a minute and 30 seconds, then it will drop like a stone to about 110, then go up to about 135. its never done this. i'll bring it down to 1500 rpm and it will go back up to 180 after about a minute. sounds like the thermostat is hanging up or something.

 

[Scaaty]

Re: thermostat temp...

Thats too hot a Stat for raw water and salt. You need 140's, so the motors will run at around 150. Any hotter bakes the salt in, or something to that effect. More people here would know. Start a new post with that question.

 

[bigbrownbuku]

Re: thermostat temp...

sounds like a sticky tstat for sure. visit a dealer and pickup the right genuine tstat for your engine.<br />merc did play with tstat temps for a bit.

 

[hotmerc]

Re: thermostat temp...

thats what i figured. i'm going to put 140's in it anyway. i was told the 4.3 motors runs a bit higher cruising temp then the V8's, but not in the 180's....

 

[hotmerc]

Re: thermostat temp...

does anyone no the proper thermostat temp for a 1998 4.3 mercruiser and would it hurt if i ran a 140 or 142 degree thermostat. it had 160 thermostats in it but it cruises at 180 degree's... cooler is better, yes?