1964 Johnson 28 HP RX-12M Cylinder Head replacement

[Visman]

Hello all - new member with a new to me boat. I bought a 1964 Starcraft with a 1964 Johnson 28HP RX-12M that is electric start. after first starting the engine it ran like crap. That is when I discovered fuel leaking out of one of the spark plug holes. At some point it had a heli-coil done that came loose (I could actually feel play between the plug and head). So I bought a new OEM cylinder head and gasket - now I just need to know how to install it (proper torque, proper gasket sealant etc.). Any help from the pro's is most appreciated? by the way I was amazed I could still get a brand new cylinder head at a reasonable price - pretty cool.

 

[Visman]

Through a link in the "top secret" file I did find he torque spec for a 1963 RX11A 28HP which is 168-192 in-lbs for the head and 240-246 in-lbs for the plug. I suspect this might be a pretty good bet.

 

[F_R]

So happens that 168-192 is correct for the head. 210-246 is correct for the plugs. For what its worth, I say go for the low end of the range on the plug (210). Seen too many stripped while aiming for 246. Retorque the head after test run and cool-down.

 

[Visman]

F_R many thanks. Do you have any recommendations for a gasket seal? I did see a bolt tightening scheme posted here which basically goes down the middle and spirals towards the outside bolts.

 

[F_R]

That is the procedure. Some gaskets are pre-coated and specifically are not to be used with any additional sealer. You can use some OMC Gasket Sealer on the old non-coated ones, if you want. Opinions vary. Use the same sealer on the bolt threads.

 

[Visman]

I see - thanks again for taking the time to answer - it's much appreciated.