1985 Evinrude 90 HP, overheating

[ace192]

Overheating, water not coming out of exhaust ports. Removed hoses from thermostate housing and drained to outside of motor. Water was cool. Bolts on thermostate housing are frozen, afraid that I might round them off. Any way to permanetly bypass or suggestions to remove frozen bolts?

 

[emdsapmgr]

Re: 1985 Evinrude 90 HP, overheating

Sounds like the thermostats are not opening. You will need to get inside the thermostat housing to see what is going on. Get a 6-point wrench if you are worried about rounding off the bolt heads.<br />Be sure the small hole(s) is/are open in the valve body. You will overheat if plugged.<br />This is not an easy job-you will need to remove the lower rear cover and may need to loosen the lower engine cover to get proper access.

 

[rodbolt]

Re: 1985 Evinrude 90 HP, overheating

if frozen that tight use an air chiesel or a good sharp hand chiesel and crack the housings away from the bolts. oxy acetetlyne works very well to simply melt the T-stat cover and the plastic block the stats are mounted in. break one off and it gets very expensive, however well maintained motors never need such drastic measures.