Carver Owners Forum

1989 Mercruiser 3.7L Thermostat question?

My twin engine Carver runs about 120 130 degrees.
Boat ran great all summer, I believe the previous owner (I just bought at beginning of year) has removed the thermostats. Should I replace them with original 160 degree ones or leave as is?

I would install them with the original 160 degree stats. The engine is designed to run at 160 - 170 degrees and you won't be burning fuel efficiently if it's not getting up to the recommended temperature. Keep in mind, you will lose some coolant when you replace the stat as it is in the manifold

I did replace both out drive impellers when I got it They were defiantly bad, maybe this is why he removed them. He was a "Diesel mechanic". I will return them to stock.