I just had my 1989 330 hp 454 rebuilt by a certified merc master mechanic. I got the boat back last week and did not try to start it until today after I put the interior back in. I cranked it twice and it locked up. I immediately started pulling the plugs and when I got to cylinder 6 some water poured out and when I got to 8 alot of water poured out. The engine will now crank over with no problems. Can this be a water reversion problem as I did have a cam installed while they were doing the rebuild. I am using the stock exhaust manifolds as well. The cam is a Lunati, # 30206 marine cam. It has 230 in. and 235 ex. on 110 lobe separation. .525 in and .525 ex. lift. The exhaust has a 3" spacer on the risers too. The motor has new speed pro hypereutectic 030 over pistons, roller rockers, rpm intake and edelbrock marine carb. It had peanut port heads but my builder said he had some large oval port heads he would give me for $250.00 and install my valves in them. The builder said it ran fine when I picked it up and I have'nt called him yet with the problem. Does sound like water reversion to you guys? Would it only occur in the back two starboard cylinders? The boat has straight thru-hull exhaust. Can it be he sold me bad cylinder heads? Any comments will be greatly appreciated before I go back to him. He will stand behind his work so that is not a problem.

With the amount of water you are talking about I would look at the riser,head and intake gaskets. Also need to find out if he decked.

You sure you have good risers and good gaskets on them? Did he run the motor with your exhaust installed?

You may want to pressure check your exhaust for leaks.
mc

thanks guys, the builder said he did run it in the boat. its going back to him tomorrow to be checked out. my only question is why just the two back cylinders, #6 & #8? would a riser problem do that? Also no water in the pan!

Risers may run fine but seep a little and slowly. Once you shut it off, the water drips down over hours or days.

with it only being on the one side, I would bet something in the exaust sys. is leaking. like stated above.

did you have a hose on it when starting ? if so never turn it on until engine fires, can run past the riser and right down into a open exhaust valve on some risers, if not look at those risers...Rob

he cleared the cylinders, installed the plugs and test ran it thursday for about 30 minutes. shut it off and rechecked for water yesterday. No Water! He fired it up and wil recheck again monday before I go pick it up. He told me that the engine did desel a little when he shut it off the first time and it may have turned over backward a little sucking water in. does this sound possible to you guys?

I would never think of starting an engine without the water flowing first. The rubber Impellor in the water pump will be toast. If that theory was correct you would never start your boat in the water because the outdrive is a foot in the water.

YUP !!!! Thats one of the biggest causes of water in cyls,,, kicks back and takes a big gulp !!!!