I was curious what's the average hour expectancy of a merc. 454,330 h.p. I know there are a ton of variables, just curious on the average amount ? Thank you

I can't give you a specific number, but I will say this. Keep a close eye on the exhaust. That's the DEATH blow to many stock motors that would otherwise run forever.

Just a thought ? I'm clue less. 400,1400,4,000 ? And the exhaust? The color, or the manifolds ?

Look where the manifolds and risers meet. If you see rust on the outside, it needs attention. Also where the manifolds bolt to the block.

I've heard of those motors going 2000+ hrs.

guess-t-meant 1000-1200 hours...saltwater with now closed cooling...less...

Sometimes it not even the hours of running, it's the hours of sitting. Engines sitting for a long time seem to be in need of service much faster than motors run regularly

Thank you all. I'm oubviously a rookie. Now, the t.r.s. and bell housing were sold on me, but the tranny is complete. Will anything other than a trs set up work ?

Dave M. the rust that you refer to -- is this primarily in salt water? I have a 2000 7.4 mpi that has a very very slight line of rust where the manifold meets the riser. I wish I could attach a picture - for you to see. The engine is 100% fresh water and about 300 hours.

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Salt water is definitely harder on equipment than fresh. But the concept is the same. Cast iron and water over time causes issues. The passages get corroded and water leaks back into the motor.

You can separate the manifold and riser and take a look. If things look OK, just replace reassemble with a new gasket. The gaskets are only a few bucks.

Thank you-- I'll get it on the list of to do's

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