How many hours before a rebuild?
 

Looking at a 89' Formula 357. Has the stock Merc 420's (454 CI) and 500 hours. I am told they are original. I know to have a compression chk done, but 500 hours seems like rebuild time to me.

Second, about how much $ per side to expect.

Wannabe

Re: How many hours before a rebuild?
 

Don't know about the 420's but my 454 Mag just gave up after 550 hrs. I think the failure was mainly due to the crappy stock merc exhaust.

A lot of those hours were salt water hours and I ran it prett hard.

Re: How many hours before a rebuild?
 

After 500 hrs they at least need a valve job. For peace of mind I'd probably do the bottom end also. Instigator here on the board, just had his 420's rebuilt at Millenium Marine. Lenny, the owner, is a reasonable and honest guy. He rebuilt my 540's and did a great job.

Re: How many hours before a rebuild?
 

PatriYacht- where is Millenium marine, Detroit area?

Thanks Wannabe

Re: How many hours before a rebuild?
 

Millenium is in Harrison Twp. near I-94 and Metro Beach Pky. 586-468-7361 He stays in Mi. over the winter and builds engines for next season.

Re: How many hours before a rebuild?
 

I'm surprised at rebuild at 500 hours. Must be related to use--I'm told 1500 to 2000 hours in normal service should be expected.

I've got a pair of MarinePower 454 EFI engines with 700 hours and they check out, at least with the diagnostics we can do without pulling engines down.

Poorsche

www.boatmat.com

Re: How many hours before a rebuild?
 

I agree, start worrying in 300+ hours if well maintained and not severly abused. We all know it takes too many years to do that many hours up north.

Re: How many hours before a rebuild?
 

I just pulled my 7.4/330hp with 703 hours. I have to change the coupler and figured I would rebuild it during the winter. My engine ran good and had good compression and would have made it another season (with crossed fingers). After pulling it I saw that it d some problems that need attention. By the looks of the engine it was in a lot of salt. I'm looking at a budget of $3k for the rebuild minus the exhaust.

Re: How many hours before a rebuild?
 

"I'm surprised at rebuild at 500 hours. Must be related to use--I'm told 1500 to 2000 hours in normal service should be expected. "

For normal recreational usage I would agree w/ 1500 hrs. Hi-performance usage w/ more WOT time reduces that.

I am not sure the engines need to be rebuilt at 500 hrs. I was just looking for opinions and estimates. The $ 3k a side is abudget amount I have.

Wannabe

Re: How many hours before a rebuild?
 

in my 6 months of high performance boating I've never seen a high performance motor go 1500 hours ...much less 2000 ......