Crankcase sealant 1958 johnson 10

[Fry300]

I rebuilt my grandfathers 1958 Johnson Seahorse 10 a few years ago. It's been a great fishing motor so far...except for the gas leaking from the crank case. There was a very minor leak after using it for a year at the end of last season. So I took it apart, inspected the parts for cracks resealed it with indian headgasket shellac and torqued everything to spec. Am I missing something? Am I not using the proper sealant? I took it on its first fishing trip yesterday, I checked under the cowl atleast 10 times dry as a bone...at the dock I noticed there was quite a bit of gas floating around in the water popped the cowl and noticed a s-load of gas. I ran it at the doc for a few minutes and noticed its coming from the crank case again.


tl:dr What sealant should I be using? Could I use a high tempature RTV?

 

[Joe Reeves]

Re: Crankcase sealant 1958 johnson 10

In years past (the time of the engine mentioned), the small horsepower models that did not use spaghetti seal between the crankcase halves simply used a coating of what was called "OMC Adhesive" which is now called " Bombardier 3M Product #847".

However, since then, many of the engines did away with the "Spaghetti Seal" altogether and a substance called "Gel Seal" is used to seal the crankcase halves. This substance hardens into a sealer with the absence of air. The following is a short paragraph on the subject taken from my database.

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 absence of air, and if called for, must be used. One other form of Gel Seal that can be substituted is "Loctite #518".

Bottom line... You can use the Bombardier 3M Product 847, or preferably Gel Seal which is also available as LocTite 518.

 

[Fry300]

Re: Crankcase sealant 1958 johnson 10

Thank you for the good information. I'm getting quite aquanted with this little motor. This will be my third time taking it apart....third time's a charm I guess.

 

[Chris1956]

Re: Crankcase sealant 1958 johnson 10

Joe, My Fat-fifty called for Perametex #1 for the crankcase. It is the fast setting-hard drying sealant. Didn't the smaller motors use that as well?

 

[Joe Reeves]

Re: Crankcase sealant 1958 johnson 10

Chris... That's something I'm not familiar with. Personally I have never heard of OMC recommending Permatex for any use excepting the gasket area under the original (1960 to 1970's) 40hp model exhaust tuning tube area, also the later 1959 35hp models.

The 1958 and 1959 V4 50hp models incorporated the spaghetti seal between the crankcase halves and I always used "Marpox Sealer" which was the only thing recommended back then before OMC came out with "OMC Adhesive"... worked for me.

Not saying that your manual doesn't recommend Permatex or contradicting you... just saying that I have never heard of it being used or recommended.

 

[Chris1956]

Re: Crankcase sealant 1958 johnson 10

Strange, as I am pretty sure I had an OMC Service manual. It wasn't many pages in a 3 ring binder. I also remember being surprized when it was recommended.

FYI - I dropped that motor into the salt water while running on plane. After looking for it for three days, I found it and dragged it ashore. I popped off the crankcase and ran some oil-gas mix thru the ports and on the crank to wash out the sand and stuff. Cleaned the carb and distributor and pull started that baby. Ran just fine. Obviously, 60 hours of salt water could not defeat 30 years of gas-oil.

 

[HighTrim]

Re: Crankcase sealant 1958 johnson 10

I have most manuals from the 40s through the 90s. Never seen Permatex mentioned myself. Most mention sealer 1000, now the 3M 847 Joe mentioned. That is all I use, it is a great product.

 

[Fry300]

Re: Crankcase sealant 1958 johnson 10

I went with your recommendation and got the LocTite 518. I just received it in the mail today, and read the instructions. The instructions mention something about LocTite Kleen and Prime. Is that absolutely necessary or is it a sales gimmick?

 

[Joe Reeves]

Re: Crankcase sealant 1958 johnson 10

Kleen & Prime isn't really needed. I never used it. Just make sure that the sealing surfaces are clean so that you will have a accurate metal to metal fit, then wipe down the sealing surfaces with lacquer thinner or acetone before applying the sealer.