Thermostat Housing Removal Problems?

[BBB2boater]

I have a 1987 200 HP Evinrude. One cyclinder head is running significantly cooler than the other (luke warm to the touch). The thermostats have never been changed so I am guessing it is time. My concern is that when trying to remove the bolts on the thermostat housing I may have trouble (18 years of salt water usage is a long time; in past engine work I have had to 'fight' bolts out of the engine). Can anyone give me suggestions how to remove these bolts if I run into serious corrosion problems. I don't want to snap a bolt.

 

[Dhadley]

Re: Thermostat Housing Removal Problems?

Welcome aboard!!<br /><br />The best way it to pull the heads off -- youll want to change the deflectors in the water passages anyway. Use some heat, patience and adult beverages.

 

[rodbolt]

Re: Thermostat Housing Removal Problems?

oxy/acetylene works for me. after that a good set of bullet point drill bits and a 1/4x20 tap.<br /> after as long as they have been in its about 17 years overdue for checking/cleaning.

 

[BBB2boater]

Re: Thermostat Housing Removal Problems?

Originally posted by rodbolt:<br /> oxy/acetylene works for me. after that a good set of bullet point drill bits and a 1/4x20 tap.<br /> after as long as they have been in its about 17 years overdue for checking/cleaning.

 

[BBB2boater]

Re: Thermostat Housing Removal Problems?

Thanks,<br /> Just a quick beginners question. Is the heat best applied to the bolts or threaded area of the block (or both)?

 

[rodbolt]

Re: Thermostat Housing Removal Problems?

usually the block and the hole the bolt passes through. try not to make the bolt glow. it tends to weaken them.<br />sometimes its not the threads that are stuck but the corrosion between the hole and the bolt. if you use much heat be aware it may warp the head surface. I usually pull them and carefully clean them and at least check it with a straight edge and feeler gauge. most times I just have them surfaced just cause. its only like 15 a head and when its done I know it is correct. the shop I use has a belt sander modified to do light surfacing. for heavy stuff its still a mill job or a blanchard type grinder.