Raw water thermostat

[bluemist]

Hi,<br />About three weeks ago I wrote in about a reoccouring condition "temperature climbing up at idle" and after a few quick revs the temp would come down and remain there, I have been going over this in my head endlessly and thought back to when I first bought the boat, I decided to change the thermostat and was given a 140* automotive looking t-stat. The one I removed was a heavy looking roung bodied 143 brass unit. Is there any difference in these two t-stats and should I change it out.<br />Also will there be any benefit or harm to gutting the present t-stat and using it as a restrictor.<br />My set-up is 5.7 260 stock, open cooling system, 1987 alpha 1 impeller in the drive which is new.<br />there is no over heat condition at any rpm except the temp creeps at idle idle when first started.<br />AL

 

[Haut Medoc]

Re: Raw water thermostat

Perfectly normal....<br />Most engines will get a little hotter than normal when started from stone cold....<br />Bump it up when you think it is warm enough & if the temp gets normal, go boating without a care... <br />As long as it operates within the proper range after the initial "spike", don't sweat it...<br />All is well.... ......JK<br />EDIT: I would use a marine tstat on a raw water cooled engine.....<br />Spend the extra dolla & get an OEM....

 

[bluemist]

Re: Raw water thermostat

What about gutting the present thermostat and using this as a restrictor has anyone done this. Is there any benefit or harm which can be done by doing this.<br />BTW Thanks for the quick response Haut medoc.<br />AL

 

[Fishermark]

Re: Raw water thermostat

Why would you want to gut the thermostat and use it as a restrictor? I see no benefit to that. In fact, you would lose the real benefit of a thermostat which is to help your engine heat up to operating temp.

 

[bluemist]

Re: Raw water thermostat

Hi,<br />Thanks for the hit.<br />Because the current thermostat seems to have trouble opening. It is a 140 not the high flow 143 which is supposed to be in this aplication. Merc no longer makes the OEM part and I'm Having trouble getting a replacement (although today I found out osco makes one) This is a reoccouring prblem 3 years now everey year a new t-stat and impeller. I figured the motors temp would not continue to creep up at idle and when running the restriction would give me the correct operating temp.<br />AL