merc 150 overheating at idle and low speed

[47aviator]

I have a 1988 Merc 150 that overheats at an idle and low speed. Does fine when running medium to wide open speeds. Impeller has been recently changed.

 

[bgbass.1]

Re: merc 150 overheating at idle and low speed

check thermostat possibe not opening all the way. or you have a blockage

 

[47aviator]

Re: merc 150 overheating at idle and low speed

Thanks for the info. How difficult is it to change the thermostat?

 

[gss036]

Re: merc 150 overheating at idle and low speed

Easy as it gets as long as you don't break off one of the small bolts. Make sure you have 2 new thermostats & gaskets if you have 2 heads.

 

[47aviator]

Re: merc 150 overheating at idle and low speed

Thanks for the help. I changed both t-stats and she's running great. That was easy.