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Cylinder Head Bolt Replacement

snakefactory

New member
Engine Model: 1979 150949C V6 Evinrude

Hi everyone,

I changed the cylinder head gasket a couple of days ago and everything went really well. I ran it with the muffs on and didn't have the fuel to keep it going very long but nothing leaked. I took it out on the water, ran it, everything went perfectly, no leaks. After running it I went to retorque the head bolts and all went well except for two of them. I'm not sure if it's because I didn't let the block cool down enough or what but two of the bolts didn't reach 20ft-lb before turning over. I'm not sure if I damaged the threads inside the block or the bolt as I had to get back to the house and will have an opportunity to get out to it this weekend and try to effect repair.

I guess my question is, if I don't have a ton of access to parts near where the boat is moored, what should I bring with me in order to try and get it fixed? I know I may need all or none of the following:

  • 2.5" grade 8 bolts stainless (3/8" diameter w/ 1/2" head - please confirm if I'm wrong on this, I don't have the bolts on me) but I'm not certain about the thread pitch of the bolts/hole for this engine
  • 3/8" helicoil kit but again, not sure of the thread pitch - does anyone know the pitch?

I had another idea that may work, I may be able to epoxy a threaded post inside the hole instead of a bolt, but this was just an idle thought vs. a real idea.

Thanks so much, you guys are always so great on this board, I've been lurking and have learned a lot.

Chris



What would you guys do if you were me. .remember I can return any extra stuff that I buy
 
Fairly sure it is 5/16 NC. Wait for confirmation before making the drive. I wouldn't go the Grade 8 or stainless steel route. Furthermore, OMC used some non-standard bolts (thread length, as well as overall length.) Don't know if that applies here or not.
 
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