78 115 thermostat housing removal

[77_starcraft]

I am trying to replace the thermostats on my 115 as preventative maintenance. The bolts are rusty and I managed to get the outer two loose, but the middle bolt head broke off. Due to the lower engine cover housing, it looks like the thermo housing will have to come strait up, which is now a problem.

I removed the four bolts on the isolator pads but that only allows the lower cover to move 1/4" or so. I started to remove the bolts that hold the gasket to the lower cover housing and gained some clearance, but the other four bolts will be very difficult to remove and reinstall. looks like I would have to pull heads and carbs to get to them.

where should I go from here? do I really have to remove the power head to fix this?

here are some of my other thoughts;
1) break the thermo housing loose from the exhaust casting (doesn't want to) and cut the bolt off (now there is nothing to try to grip though). now the housing can be removed an the bolt removal process started (drill an tap)

2) continue to remove the other 4 bolts (+carbs & heads) and lower the lower cover housing enough to pull the thermo housing off and extract the bolt. I just R&R'd the head gaskets, can I pull the heads and reuse the gaskets? the engine has not been started.

3) put the two bolts back in and pretend everything is happy. (just kidding)

4) take it to a outboard shop and spend money I don't have.

It also looks like the thermo installation will be a PITA. I have read about the zip tie method, any other tips here would be good.

thanks

 

[iwombat]

Re: 78 115 thermostat housing removal

You really shouldn't have to remove the powerhead to address this. Removing the heads, especially the port head would help with clearance. You might try tilting the motor up and using penetrating oil to lubricate the holes in the t-stat cover. Generally speaking, that's where the bolts hang up - on the unthreaded part inside the guide holes. Removing the powerhead is the long road to proabbly more problems than you're ready to tackle.

Plan B would be to locate another t-stat housing and have a carnival with the sawz-all.

 

[R.Johnson]

Re: 78 115 thermostat housing removal

Removing, and replacing the thermostat cover is not a fun job under any condition. In the long run, with the problem you have, it would probably be faster, and easier to pull the power head. This is really not as bad as it sounds. After all, the whole block will lift off intact.

 

[77_starcraft]

Re: 78 115 thermostat housing removal

Generally speaking, that's where the bolts hang up - on the unthreaded part inside the guide holes. Plan B would be to locate another t-stat housing and have a carnival with the sawz-all.

I was able to break the housing loose and the bolt was frozen in it (luckily not the exhaust housing). A new housing is about $40, so I used various tool of destruction to remove the housing from the bolt (except a torch, as fuel has been leaking everywhere). both t-stats were frozen open, so the job was not for nothing.

thanks for the help. next step is to spend more money and reinstall.