Wateer leak mercury inline need advice

[speegt]

I recently found a small water leak around the number 1 plug on a mercury inline 150 hp. I got a new gasket cleaned the back cover and used some rtv and reasssembled . After i got it back together and i gave the rtv silicone 2 days cure time now i have a water leak around number 3,4 5 plug why?i used the rtv because there were some pitting in the aluminum cover .is there a secret to these gaskets back there ive replaced alot of gaskets on motors before and never had this problem i took it back apart and cant figure out why it was leaking any ideas on this appreciated.

[Capt.Insane-o]

The only "real" way to remedy this in my own experience, without using RTV or goopy sealer is to have a machinist square up the surfaces of the water cover. Generally if the leak is just a dribble or a few drops here and there ignore it.

[speegt]

i take it then this is a fairly common problem with the leak around the plugs ?i guess i can try and reseal it any tips on rtv placement am i not getting enough placed around the plug holes ?

[Capt.Insane-o]

The last one that leaked pesistantly on me and I did'nt have access to a mill I used 5200 on. Never had much luck with RTV on anything.

[Mark75H]

i take it then this is a fairly common problem with the leak around the plugs ?i guess i can try and reseal it any tips on rtv placement am i not getting enough placed around the plug holes ?

Its only common if the motor has been overheated. I have successfully used gasket sealer and hand cut gaskets, they usually seal up with a new gasket. The $80 factory gasket is a little thin. If it takes a file or milling operation, I'd take a serious look at the bores after honing ... the motor has been REAL hot.

A small amount of water is OK as long as its just a dribble of fresh water. A leak of salty water will eventually be fatal.

[Bruster]

I've seen dozens of Mercs that leak around the spark plugs that have never been overheated. It's just a bad design on Mercury's part. The cover can not seal tight and allows water to migrate and eventually corrode to the point that water will pass. The fix I use that is 100% effective is to pull the power head and remove the water jacket cover. clean both surfaces of the old gasket. Clean the base gasket at this time carefully at this time too. I then use a oak block and 120 grit sandpaper to remove any high spots on the block and water jacket cover. With everything clean you are ready to assemble. I coat the gasket with 3 Bond 1194 Liquid Sealer. I make sure I have a nice coat of 3 Bond (don't skimp here) on both sides of the new gasket, especially around the spark plug holes. Re-assemble with new bolts (or bolts & Nuts).

http://i.ebayimg.com/19/!B,UwlNQBmk~$(KGrHgoOKioEjlLmfBoYBKrC!IU9EQ~~_12.JPG


Its only common if the motor has been overheated. I have successfully used gasket sealer and hand cut gaskets, they usually seal up with a new gasket. The $80 factory gasket is a little thin. If it takes a file or milling operation, I'd take a serious look at the bores after honing ... the motor has been REAL hot.

A small amount of water is OK as long as its just a dribble of fresh water. A leak of salty water will eventually be fatal.

[Mark75H]

Looks like good stuff. I agree, thorough cleaning is important. The old gasket is often hard to see, but very important to remove.

How do you know the motors have not overheated at some point?

[JP Love]

1194 a real good sealer and the best on engine base

[speegt]

thanks for all the great advice , though im not sure if it was ever overheated from the past mercurys ive had apart i would say this one has not been overheated it just has no signs of it and it runs great .powerhead was rebuilt a few years back and i could easily telll that when i took that back cover off , i have it cleaned very good ill get some of that sealant and try again.

[Bruster]

One example:
I did this repair on the XS on my Carlson 2 years ago, I'm pretty fussy with that. It just started to drip. When I dis-assembled it there was corrosion that just developed between the gasket and aluminum block/cover and the gasket just falls off. Around the bolts, the gasket is stuck tight to the aluminum with no corrision or leaks. The lack of clamping pressure around the sparkplugs with a relitively thin cover plate is the design issue I'm speaking of. The 3 Bond glues the gasket and creates a long term elastic seal, so the lack of even clamping pressure is less of an issue. I NEVER use silicone or RTV sealers. The 3 bond seals crankcase halves to gaskets 100%.

Overheating can cause this issue, but it's just not a prerequisite.



Looks like good stuff. I agree, thorough cleaning is important. The old gasket is often hard to see, but very important to remove.

How do you know the motors have not overheated at some point?

[Bruster]

http://cgi.ebay.com/Three-Bond-Threebond-1194-Liquid-Gasket-Sealer-/160419462332?pt=Snowmobile_Parts_Accessories&hash=item2559bebcbc


thanks for all the great advice , though im not sure if it was ever overheated from the past mercurys ive had apart i would say this one has not been overheated it just has no signs of it and it runs great .powerhead was rebuilt a few years back and i could easily telll that when i took that back cover off , i have it cleaned very good ill get some of that sealant and try again.

[Capt.Insane-o]

3 bond works great, I just usually have a tube of 5200 about. :)