Mercruiser 4.3 water in block

[btowle]

I’ve been dealing with my boat service department since last summer about my mercruiser not starting. I had not used it since they winterized it and it didn’t start after that. They initially diagnosed it as water in the cylinders and couldn’t determine why so they took the engine out of the boat to work on it over the winter. After countless calls and promises someone would get back to me I was just informed they couldn’t figure out the cause. Apparently the block is not cracked and the head gasket is fine. Their conclusion is there is something occurring inside the block causing the problem and there isn’t anything for them to do about it and it makes no sense putting the engine back together in the boat. They said the boat will start but stops soon after due to the water issue and it either needs a new block or a new engine. This has been a reliable boat dealership in the past but some of the recent issues I’ve had with them leaves me skeptical they are not being honest with me. Does anyone have any experience, input or suggestions about the water issue I described?

 

[dubs283]

Have no idea how they are troubleshooting but for them to say the water is getting into the cylinders through the block but they feel the block and head gaskets are sound does not make sense. A cracked head could leak water into the combustion chamber.

Most common cause of water in the cylinders from just running the engine is failed exhaust manifold, riser or riser gaskets

 

[Scott Danforth]

Pressure test the cooling jacket

Being a 4.3, this is an older boat

Salt water or fresh water? If salt, most likely bad exhaust manifolds/elbows

Regarding the boat yard, my guess is they are not a certified mercruiser service center

 

[btowle]

Pressure test the cooling jacket

Being a 4.3, this is an older boat

Salt water or fresh water? If salt, most likely bad exhaust manifolds/elbows

Regarding the boat yard, my guess is they are not a certified mercruiser service center

A little of both salt and fresh water and I flush it after using in salt water. When I asked them next steps they said they didn’t have one because they are not a certified Mercruiser service center. I’ve been taking my boat there for years and this is the first they mentioned it.

 

[Rick Stephens]

If I had to guess, the winterization was done poorly and the motor is freeze damaged. They really stated that the motor stops running because of water ingress? Wow, that takes a hole in the head or intake mani. As noted, without a pressure test of the cooling system it is all guess work.

There might be a chain of facts enough for action. On the other hand the actual motor is not a big dollar one, and certainly doesn't have to be a mercruiser sourced replacement.

 

[Bt Doctur]

Water in multiple cylinders? Then suspect poor winterizing. Question them on their procedure.

 

[Scott Danforth]

do a compression test. are all cylinders between 125 and 150 psi?

do a water jacket pressure test. does it hold 15psi?

 

[achris]

It's more what they didn't say that concerns me. Where's the exhaust manifold pressure/crack test?

I'd also be asking for an EXACT Winterizing procedure (looking for 'drain block and manifolds. Clear drain holes').

Chris...

 

[btowle]

If I had to guess, the winterization was done poorly and the motor is freeze damaged. They really stated that the motor stops running because of water ingress? Wow, that takes a hole in the head or intake mani. As noted, without a pressure test of the cooling system it is all guess work.

There might be a chain of facts enough for action. On the other hand the actual motor is not a big dollar one, and certainly doesn't have to be a mercruiser sourced replacement.

I will need to inquire again on the different testing, if they even did any because they never mentioned anything about testing other than the head and block look good. As far as the motor, it would be a big ticket item for me because they are trying to sell me a new one for $12,500. Another boat dealer had a little lower price quote with several hours for the install. I’m not in a position to buy a motor when I feel I’ve been ripped off with limited options to do anything against this boat dealer.

 

[Scott Danforth]

A reman long block and new manifolds will be under $4k. Then swap the other stuff over. A 6.2 bobtail is about $12k