fund razor

Saw a drip.

Figure if they are leaking in....they are leaking out.

So... gonna change all 4.

Any cautions? Keep old gasket material out of block?

Do you guys use a sealer to keep em in place?

They are OMC... but are the square kind like a merc alpha.
4 slots around the outside.

Thanks.

Island Time

Fund razor,

All the manuals I have read say no sealant but I have been tempted to look into something. A leak cost me 1 of my engines last fall through the riser / manifold gasket.

I bought new aluminum moore manifolds off ebay and am switching to fresh water cooling on my new engines. The new gasket is stainless and the manifold / risers are aluminum. I need to find something that will not destroy that combo and last. Will let you know if I find anything worth while.

cloudmaster_321

Mine are doing the same thing with the stock merc risers on a 454. i put new gaskets in during the summer last year, and now i still have rust stains going down the sides on both sides. I didn't use any sealant, and i'm wondering if i should have.

jmherbert

If they are the "blue" type, I've been told to use blue hylomar or copper coat on both sides of gasket.

I've also been told not to use anything...

I'd use copper coat OR blue hylomar. Copper coat is better suited to high temps. I've used it to help seal up copper headgaskets, and it works excellent on those.

PS; I am done with that F$c&ing wet joint, I've ordered Revolution exhaust for my boat. Now all it can leak is exhaust.

cloudmaster_321

I know the gaskets i had were just a metal crush gasket.........i was also pondering using the high temp orange sealant

jmherbert

If they are the OEM steel/graphite ones, you shouldn't need anything. Torque per Mercruiser is 25 ft /lbs.

For the blue gaskets, I was told not to use any hardening sillycone, like the red stuff.

I would check to see if the mating surfaces are flat. I think mine were warped. It would not leak under a garden hose test, but on the motor (read; when @ operating temps) the floodgates opened.

fund razor

I haven't been able to see mine leaking.

But early last year I touched up the manifolds and risers with fresh paint and I could see a small stain that is light in color where some moisture obviously came out. Must have been on a really long run last fall.

I have no water collecting or anything.

I was kind of going for prevention, rather than fixing a major leak.

Again... OMC Cobras, very similar to mercs.

fund razor

OK...

so we have 1 "no sealant"

1 "maybe sealant"

1 "yes and no"

1 "maybe"

So.... that's 2 maybes, 2 nos, and one yes.

looks like no sealant is winning by a small margin.

FOUNTAINATLAST

Definitely good prevention to change those gaskets, I'm in the process of doing a valve job on an OMC that had leaking gaskets sat all winter and destroyed the valve seats...

I to have heard the use/don't use stories of sealant on the risers, whether right or I wrong I always use a small coating of silicone on the gaskets unless there the metal crush kind. If there metal they usually are already coated so no need.

fund razor

Thanks. I have asked around town too.. and most guys seem to think that there is no problem as long as it is a small amount of high temp flexible sealant.

I think that I will wait and see what they look like when I get them off. Just did the exhaust manifold gaskets and they were really brittle and crusty. I am guessing that the risers are the same way... just not really leaking yet.

I was thinking that a light coat might help keep them in place since the tolerances on the passages are so close.