gasket sealant question for 1958 5.5hp Johnson

I replaced the water pump on this 1958 5.5hp johnson. In doing so I removed the motor. I am replacing the gasket that goes between the motor and exhaust housing. Should I put sealant on this? My repair manual does not mention if I should or not.

Thanks,
Gary

Re: gasket sealant question for 1958 5.5hp Johnson

No sealant needed on the powerhead gasket. More important is the question you didn't ask: Make sure the seal parts are all in good condition at the top of the shaft. Use a new 303355 gasket and 303347 o-ring. If this seal leaks, it allows water to enter the crankcase through the bearing and it is good-by powerhead.

Re: gasket sealant question for 1958 5.5hp Johnson

Yes I made sure to replace that cork gasket and O-ring with new ones. Now my question is, do those effect the compression any? Someone told me they did, true or false?

Thanks for the replies

Re: gasket sealant question for 1958 5.5hp Johnson

Gasket Sealers)
(Usually available at any reliable automotive parts type store)
(J. Reeves)

Do Not use any type of sealer on outboard carburetor or intake manifold gaskets as this would cause blockage of various fuel/air passageways. Also, there are new type gaskets, including head gaskets, which are used through out the engines that are coated with a substance that gives a shinny appearance to them. These gaskets are coated with a self sealer and are to be installed as is.... no sealers! Older style head and fuel related gaskets that are not coated with this substance are to be simply coated with oil.... nothing else.

All other gaskets (hopefully I've not overlooked anything above) should be coated with Gasket Sealer (the type that comes in a can that has a small brush in its screw off cap). This also pertains to some water pump installations that use a gasket between the plate and the lower unit housing.

Marprox Sealer 1000 or OMC Adhesive or Boat Armor Sealer 1000 (same substance) should be used on any metal to metal or metal to plastic surface (such as impeller hsg to plate) to eliminate air leaks. It should also be used on the Spaghetti tubing that is used on many powerhead crankcase halves, lower unit skegs, etc. I have found that this substance works quite well on various "O" Rings such as what are found on lower unit carrier and upper driveshaft bearing housings (Note that this substance is obviously not to be used on all "O" Rings).

DO NOT use any sealer on the large "O" Rings that are used on the upper and lower crankcase heads (The housing/heads that slide over the top and bottom of the crankshaft). On those "O" Rings, use only a coating of grease.

The exception of surface to surface contacts pertains to the later model matching crankcase (block) halves (which does not incorporate spaghetti tubing) which call for "Gel-Seal", or any other surface that calls for Gel-Seal. This substance seals in the absense of air, and if called for, must be used. One other form of Gel Seal that can be substituted is "Loctite #518". Nothing else that I know of will do!

I advise against using silicone or permatex on a outboard engine. It simply will not function properly. The exception to this (as per OMC's recommendation), is to use the black Permatex (heavily) on the gasket 306242 which seperates the inner exhaust tube from the exhaust housing on the 1959 35hp and 1960 to 1970 40hp OMC outboards.

http://stores.ebay.com/Evinrude-Johnson-Outboard-Parts-etc?refid=store

Re: gasket sealant question for 1958 5.5hp Johnson

qmarshal, no the seal won't have any effect on compression. BTW, glue the cork gasket to the plate with some kind of suitable sticky fuel proof cement to keep it from mooshing out. Mooshing, that's squishing in up north talk.