1977 70 hp johnson thermostat housing gasket

rodsnguns

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I am soon replacing the thermostat and gasket on my 70 hp 1977 Johnson. Should I put RTV silicone on the gasket material or install it dry. And if the silicone is recommended, is the black the best , or is the blue or red just as good.
 

racerone

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Also replace the 2 rubber grommets in there.---A very thin coat of a gasket sealer ( Permatex ) is all that is required.----Many folks use way too much.-----Dry is better than RTV oozing out.
 

rodsnguns

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Also replace the 2 rubber grommets in there.---A very thin coat of a gasket sealer ( Permatex ) is all that is required.----Many folks use way too much.-----Dry is better than RTV oozing out.
Yep I think I have the grommets too. I would probably just put a very thin film of sealer on both sides of Gasket, hardly enough to ooze out.
 

Crosbyman

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Dry fit should do.. we are talking water not fuel. At worst even a small drip will probably close up after a while due to mineral build up but a thin layer of goo won't hurt either.
 

rodsnguns

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Yep I think I have the grommets too. I would probably just put a very thin film of sealer on both sides of Gasket, hardly enough to ooze out.
I only see 1 grommet in the parts breakdown page aside from the ring for the thermostat itself. Should I do the spring and the pressure control valve too? Or should the spring and valve be OK unless grossly gunked up.
 

rodsnguns

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Make sure the cover is clean and FLAT.----All aluminum castings warp with time.
I only see 1 grommet in the parts breakdown page aside from the ring for the thermostat itself. Should I do the spring and the pressure control valve too? Or should the spring and valve be OK unless grossly gunked up.
 

racerone

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????----There are TWO grommets in there !----One for each poppit valve.----One shown in the picture for clarity.----And quantity 2 required in the part listing.
 

saltchuckmatt

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Really, just use common sense....old engine use older stuff, newer really clean motor, buy new stuff. If you buy "kits" everything is cheaper and you get extra parts. Comes in handy later.

Single parts, nope.

Simple really. I'm sure you can handle it, you seem to have knowledge but might not quite be confident in your abilities yet.

Go for it
 

rodsnguns

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Really, just use common sense....old engine use older stuff, newer really clean motor, buy new stuff. If you buy "kits" everything is cheaper and you get extra parts. Comes in handy later.

Single parts, nope.

Simple really. I'm sure you can handle it, you seem to have knowledge but might not quite be confident in your abilities yet.

Go for it
Plenty confident. I just dont like to have to go back and do something twice or half way. I was looking for a kit but couldn't find one as of yet but ain't giving up on the Search yet.
 

rodsnguns

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Really, just use common sense....old engine use older stuff, newer really clean motor, buy new stuff. If you buy "kits" everything is cheaper and you get extra parts. Comes in handy later.

Single parts, nope.

Simple really. I'm sure you can handle it, you seem to have knowledge but might not quite be confident in your abilities yet.

Go for it
In My particular application, every (kit) listed only comes with the tstat, tstat ring seal , and the cover gasket. Any other internals would have to be ordered separately, piece by piece.
 

racerone

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??----You take thing apart.----Inspect.----Order / replace what is needed.----That is the way I have done this work for many years.
 

saltchuckmatt

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In My particular application, every (kit) listed only comes with the tstat, tstat ring seal , and the cover gasket. Any other internals would have to be ordered separately, piece by piece.
Kits typically are more than you need, and I'm speaking generically. Drop the stat is hot water with a thermometer and watch what it does...as far as the spring, testing outside of the outboard is more complex.

Good luck with you motor.
 

rodsnguns

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Okay?So here is an update on my thermostat, housing questions.I've been posting. I took the thermostat housing off And there is no thermostat, no spring, no pressure relief valve. The only thing in there is the two little rubber grommets. This motor has been sitting up for a period of time so apparently somebody maybe thought it best that it might run better without a thermostat in it. But I wouldn't think so. So, grrrrr !
 

rodsnguns

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So I need help. It is obvious where the two grommets go because they were in there And I removed them. But I have no idea whether the pressure relief valve goes in the upper hole or the lower hole as well as the spring. The outer housing has locations where a spring could go in either hole.
 

rodsnguns

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Ok, did some diagram research. So naturally all of the missing parts require 2 each. Springs, pressure relief valves, and grommets. Ain't it just great. Cha-ching, again.
 
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