Sealing Mercury KD-4 two piece tank

[clockguy2]

Some folks coat cork floats with super glue to seal them. It is impervious to gasoline. I recently washed the oil out of my tank with straight gasoline and squirted a tube of super glue into it after the tank dried. I rolled it around so that the glue coated the seams. I have not had the chance to check if it worked or not, but I thought you might like a promising cheap alternative to parting the tank halves.

[bob-d]

Thanks all for the suggestions. Brought the tank halfs to a machine shop.He put both pieces on a level plate fixture, and it definitely wobbled. He said if he put on a belt sander it would make it worse. Judging from the level of high end measuring and milling machines etc that was in the shop,this guy knew what he was talking about, and just wasn’t looking to take my money. Told me to try the sandpaper on glass method, and possibly Loctite 380 industrial super glue. He said it is one of the strongest adhesives that he knew, but didn’t know how it would stand up to Ethanol.
Just wondering, does anyone know what Mercury used originally to seal the tank halfs? Possibly a gasket?
Bob D

[dave-bernard]

yes a gasket and sealer.

[jeff-register]

Hi Louis!
Yes I agree! The prep work is the key to a great seal. I changed some 1965 Cadillac heads & there wasn’t any exhaust manifold to head gaskets. The great machining sealed the mating surfaces good enough to have no leaks. The OMC gasoila is a good sealer too. The 518 works well for crankcase sealing too. Need to use the prep spray too. MUST be a clean flat surface before applying.

[RICHARD A. WHITE]

Red-Kote….Fuel tank liner….I have sealed a KD4, and Big Four tank…Can clearly says "Does NOT stick to plastic, fiberglass or Carbon-fiber tanks or to plastic parts inside tanks"…."Not for Racing fuels unless you contact their chemist first"…..

http://www.richardsoutboardtools.com
classicomctools@gmail.com

[green-thumbs]

I too was afraid to split a tank open until I had a tank that simply gushed water thru gap when
washing it out. There are a lot of EXOTIC "cures" for a two piece cast tank leaking at the seam(s)…I have seen screws installed in an attempt to pull the seam tight at a leak, lots of
gobbed on tar like substances and even a tank welded together…got to admit that worked.
The lazy man’s method (mine anyway) is to split the tank halves, clean seal surfaces and degreaase. Then apply a product called Seal All to gasket and to gasket surface of the
BOTTOM half of tank, clamp it down and let it cure overnight. BTW the sealer cures by
evaporation of solvent…allow Seal AlL to become tacky before assembly…very strong fumes…outdoors only. After cureing overnight trim gasket and apply
Seal All to top half gasket surface allow it to become tacky ,assemble and tighten screws and leave it be for a day or so.
If anyone is interested I still have the picture series posted on now gone Antique Mercury
site before AOMCI crash.
Louis
I have done 5 tanks and have not yet run across a warped surface. In fact the milled surfaces
were extremely flat…I checked with a straight edge and found no light showing…that amazed me as even a 1/1000 inch gap will show light. They were all that good. On the other hand a purchased rewind assembly did not line up with threaded holes in tank(s) requiring
some "fitting."
The method, material and results are simple, easy and effective. A tube of Seal All and a roll
of gasket stock about $10 will do 2 tanks and leave enough gasket cuttings to regasket a couple of KD/WD powerheads. Lazy and Cheap that’s me.

[mike-stroz]

I’ve used something called Red Kote, recommended to me by a small engine mechanice near where I live. It comes in a quart (I may be wrong about the size) can and you can either brush it on or shake it around, and it even encapsulates surface rust so the tank doesn’t need to be perfectly clean.

[beezer]

Have used ThreeBond 1184 liquid gasket maker,best stuff on the market. Have done 2 Wizard tanks 1 KB4 tank and a Bindix tank and a Flambeau tank. If you have to use a tank sealer use Red Kote it’s good and easy to use.

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