water in cylinders and oil

Have a 1984 mercruiser 228 (GM 305). Ran great all summer and died on labor day after sitting for 2 weeks. Started hard but ran well for 10 mins in am. Went to start later in day and starter broke in half. Now realize after the fact it was hydrolocked.

Just drained oil and it was full of water. Pulled plugs and 2 of middle cylinders on port side were full of water. Manifolds, risers and gaskets are new last year.

I have 2 questions:

1) The last time I used boat I did a lot of tubing, and in hind site, felt like boat was bogging which it has never done. I hadn't used boat since that day. My theory is the water could could have come in through port exhaust (bad shutters) with a lot of stopping quickly. Does that sound reasonable? Would that explain water in cylinders and oil?

2) I drained oil and replaced. I pulled plugs vacuumed sprayed heavy with seamfoam and filled with pbblaster. i can't run yet bc I have to replace starter. What are the chances I can save engine?

Re: water in cylinders and oil

How much water in the oil are we talking about. It sounds like you have cracked block or cracked heads or both.

Re: water in cylinders and oil

Hard to tell how much water. It was grey and mixed fully. Could be as much as a quart or two tops

I certainly understand it could be a cracked block or heads but under the circumstances don't believe its the most likely culprit. Boat ran perfectly when I docked it. Didn't overheat. Temp and oil pressure fine.

I am going to replace starter and pull risers and check manifolds and shutters this weekened. I do have a sierra green gasket no that side as well.

Do you guys recommend running kerosene through engine to get water out? Any other tricks?

Re: water in cylinders and oil

othelloears said:

Hard to tell how much water. It was grey and mixed fully. Could be as much as a quart or two tops

I certainly understand it could be a cracked block or heads but under the circumstances don't believe its the most likely culprit. Boat ran perfectly when I docked it. Didn't overheat. Temp and oil pressure fine.

I am going to replace starter and pull risers and check manifolds and shutters this weekened. I do have a sierra green gasket no that side as well.

Do you guys recommend running kerosene through engine to get water out? Any other tricks?

Click to expand...

Ayuh,.... It oughta be Easy to tell how much water entered,...

How far Over-full is it on the dipstick,..??

Don't use anything but Oil in the base,...
Change the oil, 'n Run it...

If it's not a cracked block, the remainin' water will steam off, with runnin' it, 'n buildin' heat...

Re: water in cylinders and oil

Yup, I recently have been down 'Hydrolock Lane' with my previous boat/engine. It turned out that the heads had rusted through in a couple of places around the valve guides. The engine ran OK, but did not reach its previous performance levels of several years earlier. Last year, I replaced the Manifolds and elbows, thinking that those were the problem; did a valve job too.

I should have run a pressure test on the cooling system, as that might have led me to the real problem. Anyway, around the 4th of July this year, the little leak turned into a big leak and hydrolocked the engine. The engine did not seem to mind too much as it was gradual, but like you, when I went to start it later in the day, it would not turn.

So, I would get the water out and some good oil back in and then do a compression test . . . then a cylinder leak test . . . and then finally a pressure test of the cooling system (you'll have to plug up a bunch of hoses, etc for that). At that point you should have a good idea of what & where the problem exists. Then you can decide on the tear down and corrective action, if any.

Hydrolocking is a tough one, because a lot of damage can be done to the 'rotating assembly' that is not clearly visible. You may find some bent connecting rods, etc, but there is probably more. It could be a roll of the dice as to if the engine is worthy of continued operation without self-destruction at some point.

Do the testing and take it from there. Post what you find out.

In my situation, I just wished (I couldda, shouldda, wouldda) that I had done the cooling system pressure test a year ago, when I had the engine apart for the valve job. It might have indicated that I needed to replace the heads, not just rebuild them. If I had done that, then, I would have been boating all summer and probably be about $5,000 richer.

But now I am boatless and poor. Hopefully, soon I will have another boat and be much poorer.

Re: water in cylinders and oil

tpenfield said:

Yup, I recently have been down 'Hydrolock Lane' with my previous boat/engine. It turned out that the heads had rusted through in a couple of places around the valve guides. The engine ran OK, but did not reach its previous performance levels of several years earlier. Last year, I replaced the Manifolds and elbows, thinking that those were the problem; did a valve job too.

I should have run a pressure test on the cooling system, as that might have led me to the real problem. Anyway, around the 4th of July this year, the little leak turned into a big leak and hydrolocked the engine. The engine did not seem to mind too much as it was gradual, but like you, when I went to start it later in the day, it would not turn.

So, I would get the water out and some good oil back in and then do a compression test . . . then a cylinder leak test . . . and then finally a pressure test of the cooling system (you'll have to plug up a bunch of hoses, etc for that). At that point you should have a good idea of what & where the problem exists. Then you can decide on the tear down and corrective action, if any.

Hydrolocking is a tough one, because a lot of damage can be done to the 'rotating assembly' that is not clearly visible. You may find some bent connecting rods, etc, but there is probably more. It could be a roll of the dice as to if the engine is worthy of continued operation without self-destruction at some point.

Do the testing and take it from there. Post what you find out.

In my situation, I just wished (I couldda, shouldda, wouldda) that I had done the cooling system pressure test a year ago, when I had the engine apart for the valve job. It might have indicated that I needed to replace the heads, not just rebuild them. If I had done that, then, I would have been boating all summer and probably be about $5,000 richer.

But now I am boatless and poor. Hopefully, soon I will have another boat and be much poorer.

Click to expand...

Ayuh,.... Keep yer chin up Ted,.... Better days, 'n a nicer boat are in yer future,....

Re: water in cylinders and oil

I have a similar cooling system & block. You ought to pressure test the cooling system. Get some line clamps and block off three coolant outlets to the exhaust, also block off the incoming water line cause it's harder to use as a pressure feed. Then add around 15 psi pressure through the remaining coolant outlet and listen for air escaping. Once that's done post back...it's the first step.

Re: water in cylinders and oil

Interesting find...I pulled plugs yesterday and vaccumed water and oiled. When I turned motor by hand (with bar) more water shot out of cylinders meaning the water was still coming in. I pulled rider and exhaust ports of manifold were full of water. I did have a green sierra manifold gasket on that side. Doesn't that tell me riser gasket failure is likely cause of water?

I have never turned engine by hand before. Should it be difficult with no plugs in? I have breaker bar with socket on crank pulley. It is hard to push. Just wondering if it is a sign engine is junk.

Re: water in cylinders and oil

So your next move is to dry out the combustion chambers. You can ground the coil wire or pull your kill switch lanyard while you crank it over without spark plugs. Just crank enough to expel the water. Then put some oil in the plug holes.
I have read criticism of the green manifold to elbow gaskets, so I use the graphite coated ones. If you suspect the manifold to elbow gaskets inspect them for water leak marks leading toward the exhaust in the middle of the manifold.
I realize your elbows and manifolds were new very recently. If you are sure your elbows and manifolds are OK, fine. But is there any chance there was trapped water over the winter causing any cracks?
Also, that does not address where the water in the oil came from. To check the cooling system you still should block it off and pressurize it.
And, yes it takes a long bar with maybe 75 to 100 ft lbs to turn the motor over by hand, remember it's turning the drive too.

Re: water in cylinders and oil

Turning the engine by hand, even with the plugs out will need a 2 foot breaker bar or something like that. So, no not a sign of a junk engine.

The key thing is to drain the water out of the block, so you can do a cooling system pressure test with air.

When I hydrolocked my engine, I had purchased a new starter and was able to crank the engine with the starter after I took the plugs out.

I did a compression test and got results that were all over the place because some water was still sitting in the cylinders and would not completely come out. Some of the cylinders only had about 100 psi compression, because the connecting rods were bent, etc. As I cranked the engine for each cylinder during the test, I could feel a connecting rod (or two) rubbing against the piston sidewall as the engine spun . . . the engine made a thumping sound as it spun. So, those are some of the things to look for as you get a new starter back in there.

In the meantime, you could do the cooling system pressure test even though you do not have a starter.

Re: water in cylinders and oil

Continued my investigation this weekend. Got new starter and riser gasket in. Cleaned out pistons and got her running. Actually ran very well and starts easy. Ran for about an hour in driveway. Thought things were great until I pulled plugs and found moisture on No.4 cylinder plug. All others were dry and showed proper signs of ignition.

Why would I have oil on only 1 cylinder. What does that indicate (head, gasket, block?)

Does anyone know whether I can get a pre-vortec (1985) new crate long block engine 350/5.7? I run in salt water and worry about condition of block on rebuilt?

Re: water in cylinders and oil

Check out Jasper Marine Rebuilt Engines. Have known several people that have bought them with very good success.

Re: water in cylinders and oil

If you run in salt water . . . and . . . are getting moisture on one or more of the plugs . . . it could mean that the cylinder heads are rotting through and spraying water into the intake or exhaust ports.

A cooling system pressure test will tell the story. Other sorts of testing may have you chasing your tail.