Johnson 15hp

[necks]

I’ve got a FDE 10-L, 1956 15hp, question about using  blueLoctite. I’m replacing Exhaust cover gaskets, power head gasket, and head gasket. After I clean the threads and screws, I was going to use blue loctite, to keep screws from coming out of exhaust covers, what do you think?. I can see that will be fun to get an accurate torque reading, with those screwdriver heads. Do they make a screw or bolt with a hex head that will work?.  Gene.

[fleetwin]

I would not use loctite… The screws need retorquing due to the gaskets and sealer setting up, not necessarily because the come loose.   I would use a good sealer (OMC/merc/yamaha) on the gaskets and screw threads.  Be sure to coat the entire shaft of the screws to prevent corrosion and help sealing those areas.  You can remove the rear lower pan easily to get at the lower screws to torque them.  The secret to success here is to retorque the screws several times after the first few outing s with the engine.

[necks]

Fleetwin, I’ve got some 847 adhesive, would that do the job?.  Are you suggesting putting the 847 or, whatever on both sides of the gaskets also, and do the same with the headbolts?. Sounds like that would be a good idea to use on all the bolts when they are removed, for whatever reason. I can’t remember ever using any sealer on head gaskets, as long as the head and block are square. Gene.

 

 

 

 

[fleetwin]

Well, I don’t think I would use the 847 sealer on the gaskets only because it sets up too fast.  It would be hard to coat both sides of the gaskets and get them installed before the 847 sets up.  847 is great sealer, but is messy and sets up very quickly.  Again, you can surely use the 847 sealer, but you have to install the gaskets very quickly to avoid premature sealer set up.    Sure, gasket sealer isn’t required on new engines/parts, but only because those surfaces are clean and flat.  Not fair to make this assumption about a 50yr old outboard, I would use the brush on liquid gasket sealer from OMC/Merc/Yamaha.  Much easier to work with and less messy.  Please do NOT use silicone goop or anything like that.  Needless to say, even the best gasket sealer can not overcome major surface imperfections/gouges/erosion, so inspect everything carefully and make sure to clean out all the threads to make sure the screws thread in without jamming.  The last thing you want is for block threads to strip out during installation.

And yes, I realize that many of the OMC head gaskets have “no sealer” stamped on them.  These gaskets have a bit of gasket sealer impregnated in them that releases with heat.  There is no harm in using a bit of gasket sealer as well though, your decision.  Gasket sealer surely has little/no sealing effect on the inner cylinder sealing surface where the metal sealing ring is.  A sealing issue in this area has to be corrected, gasket sealer will be blown out quickly.  The gasket sealer used on the outer edges will help ensure there are no minor external water leaks though.

[necks]

Fleetwin, thanks for the advice, I resealed a lower unit on my 1957 Johnson 35hp, awhile back using 847 sealer on the rubber seal, low and behold I had to take it back apart 10 minutes later, and had quite a time trying to get apart, couldn’t believe how tight that clamshell stuck together. I’ll see if I can round up some of that liquid gasket sealer, good to know. Gene.

[fleetwin]

Well, the 847 is ideal for the clam shell spaghetti seal because it does dry quickly and will hold that spaghetti seal in place.  Otherwise, it has a tendency of popping out of the groove, especially in the middle of the assembly process.   I laugh when folks claim those clamshell gearcases are easy to work on.  True, most anyone could probably get one back together and working…  But, sealed up properly, is another story indeed.

I feel your pain, nothing worse than having to pull one of those clamshell gearcases back apart after assembly.  Cleaning up that 847 sealer is a royal pain in the butt.  Again, the 847 is great sealer, but only when you can get the pieces together quickly before it dries.  In the case of the clamshell gearcases, you actually want the sealer to set up before trimming the ends and assembly to ensure it stays in place during assembly.

[crosbyman]

my last clamshell was  redone  3-4 times due to the shock absorber in   my 5.5 being streched.   anyway  got soldered down to 6&11/16th.

I installed a spaghetti a bit  thick  (.114)  and it did  sqwash down nice  +   shift  +drive + prop seals replaced   and..ended up with 15 psi  on the  final pressure test

the secret may be thicker saghetti  🙂

 

 

 

 

 

 

 

 

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