1989 225hp OMC o/b thermostat Replace - metal ring

[adustman]

I just put new stats in my omc, and on the port engine, I removed the cover, removed the rubber gasket, and put the new gasket and t-stat (screws onto gasket in middle) back in. I notice the small (about 1") rubber seal on the inside of the block. I guess this is where the stat expands into and seals? Now the odd thing. I opened the covers on the starboard engine and there were two metal rings that looked like they would hold the rubber washer just lying in the bottom of the block. What are these? The rubber rings didn't even fit back into the block nor the metal because they were just a bit too small. What is supposed to be under the t-stat cover? I know the rubber seal with the stat. But what goes where the head of the stat sits on the inside of the block? Thanks!

 

[clanton]

Re: 1989 225hp OMC o/b thermostat Replace - metal ring

The seal inside the head is the seat for the thermostat plastic housing, which is the pressure relief valve, which is controled by the water control valve on side of block. The seals should have been replaced with a seal without the stainless cup. Correct pn is in a service bulletin. Dealer should have this info.

 

[Dhadley]

Re: 1989 225hp OMC o/b thermostat Replace - metal ring

The correct assemblys are black. If you have the old white ones, they need to be changed.<br /><br />Good luck!