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joeall

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When reinstalling the exhaust manifold do you recommend coating the mounting bolts with either a loc tite material or copper antisieze coating?
 
I always use nickel....some will argue....but why argue with success?
 

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Copper is fine, it has been used for decades on automotive exhausts, which run far hotter than these little outboards.
It’s rated to 1800F. Your outboard exhaust will never get near that hot. Aluminum melts around 1200F, if your exhaust got anywhere near those temps, undoing the exhaust screws will be the least of your problems.
Incidentally, the service manual states, “Apply OMC Gasket Sealing Compound to threads of retaining screws. “
This is to keep water out of the threads, controlling corrosion. Antiseize, (copper or Al), also pretty good.
 
My son is a highly educated and experienced chemist very very talented in all fields. He warns me of negative attributes when mixing copper with stainless....since so much stainless is used in marine and aviation. He also recommends caution in use with non ferrous materials like aluminum. I stay away from copper anti seize in some applications. I do have a couple of bottles here, however, which I use on general steel assemblies.
 
Price is pretty much the same. In major overhauls heavy diesel marine, we keep both on hand. Use a lot of it. 4 years later, on next overhaul, things come apart without problems. Food for thought....a "refresh overhaul" on an 8000 HP Peilstik engine, the boss gets 2 million. Usually start with 7 or 8 guys, then 3 or 4 of us finish up and test run. The engines were designed to run 20 maybe 30 years but many of the ore carriers on lake Superior now are 50 years plus with the Pielstik. Navy has some still running well too. 6 ships are in Charleston Cooper River. Each has 3 main engines, all Pielstik. The Cape Douglas for example was laid down in 1972 out of Sweden....ha! Boss is Swede.
 

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Edchris177 said:
Copper is fine, it has been used for decades on automotive exhausts, which run far hotter than these little outboards.
It’s rated to 1800F. Your outboard exhaust will never get near that hot. Aluminum melts around 1200F, if your exhaust got anywhere near those temps, undoing the exhaust screws will be the least of your problems.
Incidentally, the service manual states, “Apply OMC Gasket Sealing Compound to threads of retaining screws. “
This is to keep water out of the threads, controlling corrosion. Antiseize, (copper or Al), also pretty good.
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Thank you for your advice! I am learning everyday and enjoying this hobbie.
 
Yes Joe. The accumulating of knowledge is essential to our well being and mental health...can help us keep this old stuff running well and reliable. There is nothing like the feeling of success when a repair job is up and running perfectly.
 
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