93 90hp force thermostat spacer question

when i removed my thermostat it did not have a spacer in it. can anyone tell me what it's for, and do i have to have it
Thanks, Rich

Re: 93 90hp force thermostat spacer question

If we are talking about the same thing, it is a black rubber "washer" grooved to fit the thermostat flange. It seals the thermostat to the head IF the spring is there. Without the spring, water will blow the thermostat off its seat and warm-up will take longer.

Strictly speaking the spacer or seat is not necessary: The thermostat has a weep hole in it so hat water will pass and activate the expanding plug to open it. SO, a little seepage around the flange could actually be beneficial--provided that the spring is present.

Re: 93 90hp force thermostat spacer question

the parts diagram shows a spacer between the seal and thermostat then the spring

Re: 93 90hp force thermostat spacer question

Oh, yeah----forgot about the steel ring. It has been so long since I opened one of those thermostats that I have trouble remembering exactly how they went together. I THINK the thermostat actually fits inside the spacer and the spacer is open at the bottom to allow full water flow when the thermostat is open--the cover is filled with the top of the thermostat and the spring, restricting water flow.

Is it necessary? Well from the standpoint that the factory does not spend unnecessary money to put in unneeded parts, yes it is necessary. Can you get by without it? Most likely yes. Can you make one? Yes, easily. Just bend up some 1/16 inch aluminum. make the band wide enough so the gasket compresses against it. That is, the surface of the band should be even with the surface of the head.

OR---You can spend 20 bucks (exaggeration) for a new one at your Mercury dealer.

Again, I believe its primary function is to hold the seat tight against the head and the spring is there to hold the thermostat against the seat-- al little bit of redundancy since the spring will hold both against the head

Re: 93 90hp force thermostat spacer question

Thanks, Frank.. I know if i could see one, i could make one. right now i have the powerhead off waiting for a new water pipe seal to get here.
thanks again, Rich

Re: 93 90hp force thermostat spacer question

They added the extra piece somewhere after the 90. Before that they didn't have the piece of metal in there.
The old style gromet fit around the edge of the thermo holding it in place.
Like Frank said it's there for a reason??
Does your thermo/gromet fit together in a groove?
Someone might have changed it to the old style???
Close up pic of the parts??

Re: 93 90hp force thermostat spacer question

. I have a 90 HP Force of unknown year (all useful numbers are gone), although I think it is a 1996. I removed the old thermostat today and saw the spacer discussed earlier. I was looking for a spacer that would fit between the face of the thermostat and the housing, but found it fits around the perimeter of the thermostat instead.


Disregard earlier version of this post.