Water passage sealant on heads

Speakrdude

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Feb 25, 2004
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942
Am am reassembling a 94 Johnson 150, and I thought I did a good job of sealing the water passages on the head when I reattached. But When test running on the muff, I get a drop or two from between the cylinder and head on the strb side head where the thereomstat passage goes through.

Do I simply remove, clean, and lay down a bead of blk rtv on the cylinder/heads, around the large passages? I remember spefically reading, "do not use silicone around the thermostat gaskets."

I warmed up engine, then re-touqued all the head bolts.


Any pointers?

See areas in circles....

 

mark1961

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Apr 30, 2007
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940
Re: Water passage sealant on heads

Did you install new head gaskets and thermostat seals? The themostat seals are part #335981.

If the new head gaskets were shiny and/or marked "use no sealant" then the answer is no and definitely not RTV (sillycone) in any case. Did you check the heads for flatness/pitting before reassembly?
 

Speakrdude

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Feb 25, 2004
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Re: Water passage sealant on heads

No gasket on heads. O ring around each cylinder only.
 

Speakrdude

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Feb 25, 2004
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Re: Water passage sealant on heads

I reused the o-rings, maybe not a good choice. No Pitting. Visual inspection for flatness looked good.(my 1/2" piece of glass isn't big enough for the 3 cylinder head.)
 

mark1961

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Apr 30, 2007
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Re: Water passage sealant on heads

Sorry, i shoud have checked before giving a general answer.....which orings did you reuse? thermostats?.....try replacing those.
 

Faztbullet

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Mar 2, 2008
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15,619
Re: Water passage sealant on heads

Pull it back off ,clean and reseal. Torque head asap when you install it, do not allow silicon to skim over.
 

Speakrdude

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Feb 25, 2004
Messages
942
Re: Water passage sealant on heads

Admiral Faztbullet, do you run a bead around only the water passages. Because, actually, there are only two. One top and one bottom.


The rest are water jacket holes in the cylinders but stop when they reach the head. So a little dab around those too?
Just the STBRD side has a small drop (leak) so I wont mess with the Port. (If it aint broke.....I'll probably break it.)
I think I let the blk rtv set up way too long on that side. That is probably the problem.
 
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