confusion as to correct thermostat temp

[admiral11harpoon]

hi everyone-happy "4th of july" to all USA people<br />I have a 1991 force 120hp.model#1201x91c,ser#022802<br />had it out last week and overheat alarm goes off-bout ***t my pants!!that thing is loud.i immediatly shut it off,pulled the cover,didnt feel overly hot.waited 15min,it started fine water was flowing well from tell-tail,could hold mine hand it for 3-4seconds.went back to dock.i got a comp tester(will check comp also),but im not sure what temp my thermo is supposed to be.i pulled mine and it is 130F.went to napa and the one that would fit-1.25in diameter is a 143F.would that be ok to use?I did get the 18-3017 impeller so that should be ok.motor has ran strong since new.ive had no probs except 1 bad cd box that went bad.great,great sight.TIA for any help. gary

 

[alcan]

Re: confusion as to correct thermostat temp

Hi Admrial<br />My OEM manual states that the t-stat should open when emersed in hot water and close in cool water. How about that for a temp? Reading farther I find that the thermoswitch is to close between 160-170 decreses far. I am sorry but that is as close as they'er going to let us get to a real number

 

[eurolarva]

Re: confusion as to correct thermostat temp

Interesting. Merc site calls out F476066-1 which is a 130 degree thermostat. However every other site calls for the 143 degree one.

 

[wrinspect]

Re: confusion as to correct thermostat temp

Took my new (used) 1992 20' Bayliner Trophy, 150 hp Force OB boat out yesterday at a local lake (Lake Elsinore) for her maiden voyage, seemed to run fine except after a few miles I did some slalom type steering, the under dash alarm came on, (coolant temp?) shut her down and the alarm kept sounding when I turned the key to the on position, waited @10 mins and it didn't sound, drove around at moderate rpms for awhile, then cruised around at 4000 rpms for several more miles then later on it did it again, shut her down etc. Ran around the lake a few more times, no problems. Any ideas?

 

[scotiany]

Re: confusion as to correct thermostat temp

Could there be a defect in the overheat circuit? There is a proceedure in the Seloc manual for testing Chryslers so, I'd assume there would be one for Force also.

 

[roscoe]

Re: confusion as to correct thermostat temp

Could be, and like is, time to change the waterpump impeller.<br />A weak/aging impeller will give you results like you are experiencing, just before it breaks and your motor overheats.

 

[eurolarva]

Re: confusion as to correct thermostat temp

I am not a force guy and I agree with roscoe about the impeller but when I was looking for the thermostat for admiral harpoon the merc site said a 130 degree tstat instead of a 143. Is 13 degrees enough of a difference to trip the overheat buzzer on the motor? Maybe switching to a 130 will prevent the alarm from going off/