jvcobra

Had to tear down my stock 502 Mag since it would not turn over after I uncovered it for the season. Found water in the cylinders and rusted pushrods, cam, springs, etc. I have no idea on how the water got in there, exhaust manifolds are fine and gaskets were not leaking. Also found a bent pushrod that would explain my poor idle. Anyway, I need advice on what to do next.

Get a new long block? New or rebuilt where would be the best place to get it from?

Rebuild what I have? Anyone sell a basic rebuilding kit for the 502 with quality components?

If I replace the heads are there any for a stock 502 that might give me a few more HP?

Sorry for all the questions but I would like to get rolling on this quickly so I still have a summer.

Thanks!

4bus

iTrader: (4)

Get the heads checked before you do anything, most likely a small crack. Has the boat been run in salt its whole life? The water jackets get thin over time.

F-2 Speedy

iTrader: (6)

ya , I'd get the block and the heads checked, do u winterize ?? if the block and heads are junk look for a complete low hour 502

jvcobra

It's a salt boat. I will check the heads and most likely replace anyway. I did winterize which probably saved the block and everything else from cracking when stored with the water in it. The port motor was also fine and started right up. I'm thinking a cracked head or reversion, but can that happen on a stock 502?

F-2 Speedy

iTrader: (6)

just to clairify, was there water in the cylinder or antifreeze, if you upgraded heads ( in ur first post ) a pair of HP 500's would be a little bump, some on here for sale

jvcobra

Sorry it was the pink antifreeze I used for winterization, the motors are raw water cooled.

TexomaPowerboater

If its a saltwater boat with open cooling those water passages will be in pretty bad shape so I would just buy complete new long blocks. Will cost just a little more than a rebuild, if you have to replace heads will likely cost about the same, maybe cheaper. You need to check the heads, and exhaust. If those need to be replaced might be better off buying a lower hour takeout if you can find one.

If you had antifreeze in cylinders from winterization then the block is probably cracked along with the heads and the exhaust. Some of that pink stuff is not rated for extreme low temperatures and it will expand when it gets slushy. It can expand right thru the gaskets if it gets cold enough. I would consider an insurance claim too, never hurts to ask.

johnnyboatman

iTrader: (5)

pour some diesel down the cylinders it will free it up then see how bad it is from there. may not be that bad to fix, the riser gaskets are prob leaking