I have 500 efi's and had one CMI E-top header leak water into starboard head. I had winterized by draining water out of system and filled block and headers with mercury's anti-freeze. I attempted to start the motor for the first time and it never started and actually stripped the gears in the starter. When i pulled header off to get the starter, water was in all 4 ports. Not sure if headers leaked over the winter or if started leaking as I hooked up fresh water flush as I attempted to start. I pulled off the header on other side which was dry. I sent header back to CMI for repair.

I did a compression check and have good compression. Is there anything else I should check before I put back together and run? Should i pull the heads and just redo them for safety sake? I have also put oil into the cylinders. I have read several previous threads of similar issues, all of which seem to have different outcomes as far as damage. Theres approximately 50hrs on motors since complete rebuilds, so im trying to avoid trashing the motor and start boating finally.

Thanks in advance for the help, as always its appreciated.
Curt

I would check and make sure there are not any teeth missing on the flywheel.

If you are worried about water being in the cylinders, you can pull all the plugs off the motor and try cranking it over with them out. It will push any water out of the cylinders out of the plug holes. If there was water in there and the motor was never started, I dont think there would be any damage to the motor mechanically.

pull all the headers and send them back to cmi,get them all fixed or all the welds rewelded...its only a matter of time before they all leak and cause future problems.

Also ck. the crankcase oil if it has water.

Definitely flush the engine with fresh oil. Run, then flush again. If water/antifreeze sat in it all winter, some would have definitely leaked past the rings and into the crankcase.

I actually did everything mentioned above. Flywheel is good. There was no water in oil and i changed the oil. Before i did the compression test, i pulled all the plugs and cranked motor, some water did come out of starboard side, but not a lot. I put oil in cylinders and cranked over again. Headers are at CMI now getting checked and repaired. So sounds like i did everything i could do at this point. Maybe i'll say couple prayers to the boating gods and hopefully ill be good to go.

Thanks everyone for the help.

Look at the exhaust valve stems (through the exhaust outlets in the head) to make sure they are not pitted or extremely rusty. If they are not rusty or pitted, then the water intrusion probably just happened when you first tried to fire it and it will be fine.
Be glad the starter broke and it didn't fire or you'd be looking at a full rebuild and a lot of bent and broken parts.

Valve stems look good. thank you for the advice. Hoping to finally do some boating this weekend.