Do I need a thermostat? Pic inside

[maharg]

I got the same temp on muffs that I do in the lake...
Merc 3.0L 140hp 1987MY

Do I need one?

 

[83vert]

Re: Do I need a thermostat? Pic inside

The motor is meant to have a stat for proper heat dissipation without it the water will circulate to fast and not cool properly. Also make it run rich.

 

[Hansolo99]

Re: Do I need a thermostat? Pic inside

Does it warm up to temp and stays there?? Never moves?? Is that running temp you showed a pic of? It appears like it's running too cold. I would check the thermostat just to be sure.

 

[DavidW2009]

Re: Do I need a thermostat? Pic inside

I'd check the temperature sender, too.

 

[jerryjerry05]

Re: Do I need a thermostat? Pic inside

Yes!!!!! J

 

[maharg]

Re: Do I need a thermostat? Pic inside

Sorry? Yes it has a therostat in it, I meant do I need a new one. It gets to that temp and stays, never goes up or down

 

[artificialreef]

Re: Do I need a thermostat? Pic inside

I am old school auto motors. Easy to test a thermostat. Take it out put it in a pot of water on the stove burner with a candy thermomiter in it and watch at what temp it opens. I think you have a sending unit or gauge issue.

 

[artificialreef]

Re: Do I need a thermostat? Pic inside

but the cost of the candy thermometer is the same as the cost of the new thermostat. Upside is you can make candy.

 

[NHGuy]

Re: Do I need a thermostat? Pic inside

Check the running temp with an infrared thermometer. If your gauge is wrong go into the Mercruiser manual to learn diagnosis info. Also, if you find the sender is wrong check the Mecruiser manua, and check your battery/electrics. Senders can provide wrong info if badly grounded. For example, I was getting bad info this spring because my cannon plug was corroded. At the same time I had a low charge in my boat battery.