1986 mercruiser thermostat replacement

[Jon 1975]

Hello I’m new to this. I have a 1986 mercruiser 3.7 liter 170. Can anyone tell me how to get to the thermostat. I bought a new one and need to replace the old one due to overheating at mid to high speeds. Thanks for any guidance on this issue.

 

[Scott Danforth]

first, welcome aboard

second, get a factory manual.

on the 470 motor, there are dozens of things that lead to an over-heat and the first one is the raw water impeller.

if the motor overheats, usually you also need to replace the head gasket.

 

[Jon 1975]

Thank you for your reply. I have the 170 motor. Is that the same configuration as the 470? It does not overheat unless I am at about 3/4 throttle and then when I slow down it cools down fairly quickly. How can I purchase a shop manual for this motor? Do you use a website regularly that you can share? Again thanks for your help.

 

[Jon 1975]

[No message]

 

[Jon 1975]

I have found the thermostat on this diagram. Do you know if it is a difficult task to get to it?