How many hours before rebuild?
#11
I hate the winter!!
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Wow, I didn't expect to see this old thread surface again. Thanks for the replies. I am going to let the motor stay for 1 more year. When it comes out next year, it will be a full rebuild, and set the motor up to run a Whipple... at least that is the way I am leaning towards now. Who knows what next year will hold..
#13
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My current 502mpi's have 600 hours on them and they run the same as they did with 250hrs when I bought the boat.
I have no immediate plans to do anything other normal maintenance.
I have no immediate plans to do anything other normal maintenance.
#15
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WOW!!! We see 500EFI's with spring issues with as low as 300 hours on them and 525EFI's as low as 250 hours. We recently did a 525EFI with 170 hours that had broken springs but that owner is know to have it on the mat no matter what.
#16
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Every 525 that we have been into have had rocker arm/valve spring issues, and that's over 50 of them. We scan every one of them and most have been fairly babied. Hell, the first one that we saw that had a broken connecting rod only had 1.4 hours over 4000 rpm. This was only the second time that the engine had been over 5000 rpm.
#17
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Lots of 500 EFI's also burned the head gaskets between cylinders in the 300 + hour range. Almost 1,200 hours is amazing! I'd say you got your money's worth out of Merc!
#18
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I have twin stock 1997 415hp 502 mpi magnums with around 930 hours in a 38 powerquest. I bought the boat in 2006 with about 240 hours and after 10 boating seasons and almost 700 hours latter I noticed no loss in performance with top end speed/RPM or any more oil consumption. These engines have only had tune ups, oil changes, fuel filters,a pair of circulating water pumps, and a set of exhaust riser gaskets. Other than that nothings been apart or touched. I know one Merc mechanic has scanned 502 mpis with 1400 hours still running.
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