Q about thermostat housing seal

[guy48065]

2000 4.3L Mercruiser.
I'm replacing the thermostat.
After scraping & cleaning the surfaces I installed a new O-ring, Tstat, oem plastic spacer, gasket (with metal rivets). I carefully centered the Tstat but when all stacked up the white plastic spacer sits proud of the gasket at least 1/16“.

Assuming the O-ring would squish down I tightened the housing in place. Nope. I can still wiggle the gasket up & down after tightened.
If I stack on another gasket I'll lose the rivet ground connection because the Quicksilver kit only came with 1 of those.

What an I doing wrong?

 

[alldodge]

The white piece should sit flush with housing. Figure out what is keeping it up

 

[alldodge]

BTW what is your serial number?

 

[Bondo]

2000 4.3L Mercruiser.
I'm replacing the thermostat.
After scraping & cleaning the surfaces I installed a new O-ring, Tstat, oem plastic spacer, gasket (with metal rivets). I carefully centered the Tstat but when all stacked up the white plastic spacer sits proud of the gasket at least 1/16“.

Assuming the O-ring would squish down I tightened the housing in place. Nope. I can still wiggle the gasket up & down after tightened.
If I stack on another gasket I'll lose the rivet ground connection because the Quicksilver kit only came with 1 of those.

What an I doing wrong?

Ayuh,...... Obviously, there's a problem with the white spacer, pull it apart, 'n see why it sits in the housing so tall,....
I'm guessing the problem is 'round the o-ring, or housing itself,.....

 

[guy48065]

I got it sorted.
My service manual shows an O-ring under the Tstat. When i looked closer at the nasty flat thing that I took out I saw it was cork. My kit came with both so I put in the new cork ring and the spacer was the 'correct' height--just a few thousandths higher than the gasket so the cork will get squeezed.