Rebuild or Not? - 502 MPI Leak Down Test Results
 

Hoping a few people can give me their opinions on my boat. I have a 502 MPI (1993) with 860 hours on it. I had a compression test done which yielded poor results in 3 cylinders. I then took the boat to another mechanic to verify compression and do a leak down test. The leak down test showed that every cylinder was leaking from the intake valve (some more than others). We could not really positively identify any leaking from the crankcase since the valves were leaking badly. I'm on the fence if I should rebuild or put new heads on and run it? I was already thinking of potentially selling the boat before any of this happened, as I wanted to upgrade. Looking for advice on next steps please. The boat is a Formula SR271. I don't want this to become an aging boat that will need more work after I do work on the motor (I.E. outdrive, etc.). Should I sell the boat the way it is, have the heads redone, or a full rebuild?

Just looking to see what others would do. I'm having a hard time making a decision.

my advice,pull heads for a valve job and new springs and run it[for a long time].i also would send the injectors for flow testing&cleaning.i used BUP from here for the injector service and recommend him.jmo for whatever it,s worth.

I would agree with Mike, you said you are interested in selling it so I would not buy new heads, just have the current ones redone. if the bottom end is sound then you can run it another year or two and sell it with the bonus of being able to tell them that the top end was redone. new heads or rebuilding is money you will never get back when you sell so hold the cost to something reasonable.

860 hoursand 15 yrs on orig 502 headgaskets is getting up there and almost good maint on a ole ' 502 . May sway the next buyer yours had the top end refresh ,even if you dont get your money back .

1993 mpi????

Rebuild heads, redo compression and leak down before it goes back in the boat. With heads off you can turn engine over to see the condition of each of the bore walls.

x2 on injectors. Even If they are all tested okay, I'm sure the filter baskets are due to for replacement or cleaning out.

Rebuild and enjoy ,,i dont care new or old you will always be tinkering with boat ,,,just my thinking

well, if your thinking of selling boat, I doubt whatever money you put in it, you wont get back if your paying to have work done. you may break even if you do the work yourself.
So, having heads freshen up could be selling point...maybe...
its all a gamble...jmo