[Z 202]

This is how my season ended. I managed to clip a rocky shoal and dinged my prop and skeg. I shut down immediately to have a look. The damage did not appear too severe, I even elected not to switch props for the ride home. I killed the bendix spring trying to get her started again. I was towed home, and when I got it on shore I pulled the plugs and found water coming out of the #2 cylinder. I couldn't get it to turn over even with all the plugs out, so I've left it with the marina.

The tear down shows the drive is fine, the shift cable was a little stretched, but the big issue was there was water in all of the cylinders. I'm not sure if this was a failure of my flappers or what. My engine did diesel a bit because I shut it off so quickly after impact, but I don't think that should be reponsbile for a hyrdrolock situation. At this point, my mechanic is unsure what lies below, while I'm waiting to hear from my insurance company. I'm having difficulty staying optimistic there though. I may have to sell off a kidney if I want to boat again next year.

[mikeyt]

Sounds like an insurance claim to me. Impact and resulting damage is (usually) a covered peril on your homeowners coverage (if the boat was scheduled) and definitely is so if you have a separate boat policy.

[Z 202]

Well the insurance company will cover repairs to the prop and drive. Damage there is minimal, probably won't even hit my deductible.

The appraiser says no way was the water ingestion related.

Guess I'm going to have to sell a kidney if I want to be boating next summer.

[ColoradoDiablo]

Sorry to hear that Z.
You and I are kinda in the same boat so to speak.(no pun intended)
I blew up a rebuilt 4.3 not long ago and am saving to get a "New" Bobtail if at all possible.
At least you have all winter to save.

Larry

[mikeyt]

Originally Posted by Z 202

Well the insurance company will cover repairs to the prop and drive. Damage there is minimal, probably won't even hit my deductible.

The appraiser says no way was the water ingestion related.

Guess I'm going to have to sell a kidney if I want to be boating next summer.

Dont always trust what the insurance appraiser says cuz after all he was hired by the company who would have to pay out for repairs. Speak with your mechanic & see what he thinks may have caused the water ingestion. If he thinks its possible the two are related (and can explain why he thinks so and is willing to put his opinion in writing) then spend a little money and get a 2nd opinion from your own appraiser.

[Z 202]

Well the appraiser is arguing resonance reversion, but from the tech documents I've read this typically causes a hydrolock while under operation at at constant RPM. My boat failed to start after an abrubt shutdown, which likely resulted in an exhuast gulp. The mechanic said there was substantial water in all cylinders and quite a bit in the pan. I had a look at for myself on the weekend. The head gaskets were fine. no visible cracks anywhere on the block or the heads, but they'll have to go to a machine shop for sure.

I've never heard of resonance reversion until now. Here's a link to a good document if anyone is interested. http://www.michel-christen.com/ExhaustElbows.pdf
Has anyone run across this issue?

[ColoradoDiablo]

Wow that is definately some new info!!
Think I'll check my risers while they are off.
Thanks Z

Larry

[mikeyt]

I've honestly never heard of this issue but after reading the 'tech' paper i sort of see what they're saying. But.... at this point the appraiser's position is nothing but a theory without any firm evidence to support it. I still think u should seek out your own marine surveyor to examine that engine. Where is the boat sitting? (near home or up on the Bruce peninsula?) I'll check with someone i know thru work this week to see if he can recommend a good mechanical surveyor.

[Z 202]

Thanks Mikey. Yes, It's up on the Bruce. I can completely understand the article and the principle, but the truth is my ingestion symptoms are not consistent with this diagnoses and more consistet with the papers own words:

If the engine reportedly failed to start after the last “normal” shut-down, consider other factors including gulp from an abrupt and/or high speed shut-down before presuming resonance reversion.

My motor did run-on (diesel) due to the abrubt stop as well. Mercurisers own tech documents state that this is a very possible cause of ingestion as well. I will be talking to my insurance later today.

[Paul F]

Many years ago, I had the exhaust flaps on my 95 4.3 work loose and settle in the "V" of the exhaust. Vibration of the flaps in the exhaust caused a pin hole in the pipe just below the water line, causing the boat to take on water.

I was told that this was another Mercruiser issue at the time. I recommend that everyone make sure their exhaust flaps are where they are supposed to be if you have a Mercruiser of the same vintage.