Water Ingestion--Need Definitions & Cures

[murphini]

Many good recent posts on stalling, no starting for a while, water ingestion, hydrolocking, water in oil, water in crankcase, links to the Mercruiser Service Bulletins, which I read and were great. But I feel like a dog watching TV...my eyes are following, but I'm not really sure what is going on.

I get the concept, need some clarification. I had a similar stalling problem recently (89 OMC 302 w/650 hours--freshwater) where boat ran great for 2 hours then stalled and wouldn't start after my son pulled back throttle too quickly after trying to get me up on wakeboard. Dead rest of day. Changed battery-slow cranking, still no start. Black battery cable hot, probably need to replace it. Oil not milky.

Then next day I went out with DonS's troubleshooting tips for the starter ready to test and the boat started right up like there was never an issue and ran fine. Ran it for 30 minutes hard, then shut down and it started right up with no hesitation.

I've owned boat for 4 summers--almost 200 hours of use, this is first time it happened. Carb rebuilt 2 summers ago. Tune up last winter. Put stabill or seafoam in the gas with each fillup

SO here are questions:
1. If water gets in, when the engine does finally start again, does it expell the water in the piston(s)--or will water still be in there?

2. During the time it won't start, is that when you take out one sparkplug at a time, or all sparkplugs (and ground coil) to see if water comes out of sparkplug holes when you crank it over?

3. Is it possible the water dissipates overnight so the engine will start the next day? Or is it more likely the engine finally cools down so it's easier to start vs. being hot after running for a few hours

4. Could this be an isolated incident or the start of something ominous?

Sorry for the basic sounding questions, but the dumbest questions are the unasked ones.

 

[Haut Medoc]

Re: Water Ingestion--Need Definitions & Cures

Many good recent posts on stalling, no starting for a while, water ingestion, hydrolocking, water in oil, water in crankcase, links to the Mercruiser Service Bulletins, which I read and were great. But I feel like a dog watching TV...my eyes are following, but I'm not really sure what is going on.

I get the concept, need some clarification. I had a similar stalling problem recently (89 OMC 302 w/650 hours--freshwater) where boat ran great for 2 hours then stalled and wouldn't start after my son pulled back throttle too quickly after trying to get me up on wakeboard. Dead rest of day. Changed battery-slow cranking, still no start. Black battery cable hot, probably need to replace it. Oil not milky.

Then next day I went out with DonS's troubleshooting tips for the starter ready to test and the boat started right up like there was never an issue and ran fine. Ran it for 30 minutes hard, then shut down and it started right up with no hesitation.

I've owned boat for 4 summers--almost 200 hours of use, this is first time it happened. Carb rebuilt 2 summers ago. Tune up last winter. Put stabill or seafoam in the gas with each fillup

SO here are questions:
1. If water gets in, when the engine does finally start again, does it expell the water in the piston(s)--or will water still be in there?
Only through evaporation from heat will it completely dry out.....

2. During the time it won't start, is that when you take out one sparkplug at a time, or all sparkplugs (and ground coil) to see if water comes out of sparkplug holes when you crank it over?
Take them all out......

3. Is it possible the water dissipates overnight so the engine will start the next day? Or is it more likely the engine finally cools down so it's easier to start vs. being hot after running for a few hours
The water will seep past the rings on a cool engine, look for signs of water in your oil, don't forgat that the water will sink to the bottom of the pan until it emulsifies.....
4. Could this be an isolated incident or the start of something ominous?
Depends, if the engine was running, it should not ingest water at all.....
If it was shut down & the following water wave hit the boat, I would say it was a one time occurance......
When was the last time the mans/risers were replaced?...
They may be on their way out.....


Sorry for the basic sounding questions, but the dumbest questions are the unasked ones.

123

 

[Silvertip]

Re: Water Ingestion--Need Definitions & Cures

The principle of water in an engine is very simple. Water doesn't compress. So when you try to start the engine, if one or more cylinders is full (or partially full) of water, that piston comes up on the compression stroke until it cannot rise further due to the water. It's like having concrete in the cylinder. Thats how rods get bent, pistons broken, ring lands broken, etc. Obviously, taking out just one plug does no good when you have 3, 5, or 7 more cylinders that may have water in them. A small amount of water will be expelled with the exhaust when the engine refires and will dry out that cylinder quickly. Water in the oil is another matter. Water is not a good lubricant so you need to get it out of the pan via an oil change.

 

[murphini]

Re: Water Ingestion--Need Definitions & Cures

Thanks for both advice posts.

1. Will change oil. Was coming up on 50 hours anyway.

2. To my knowledge, Manifolds & Risers never have been changed. I'll look into that during off-season layup. I'll get quote/estimate from my local shop that services OMCs.

3. Hard choices.... boat runs great, transom is firm, and I have a lot sentimental attachment to it.

But, Soft spot(s) in floor near ski locker and back bench seat are growing, it's OMC, and possibly needs mainfolds/risers...and the kicker, my wife would like a bigger boat to fit our teenage kids and their friends. So:

1. Sell as is, of course disclosing issues
2. Fix and sell, getting back pennies on dollar
3. Fix and keep.

My preference is 3, then 2 then 1 Any wisdom would be appreciated.