Impeller failure: Long term engine impact?

[poacherz]

Hi,
Looking at purchasing a 2002 Sea Ray 220 with a 6.3l mpi engine. The boat has a full service history. We reviewed the service history and in April 2006 the engine overheated due to impeller failure. All exhaust boots on engine, lower shift cable, outer exhaust tube, u-joint bellows, exhaust shutters melted. Over $2K was spent in parts/labor. Compression test results after the repairs were 170 to 190 with the majority of cylinders being 180/185. We have been told the boat has been fine when used subsequently, albeit only used infrequently over the past few years.


Question: Any concerns about engine damage and long term engine reliability? Should we pass on the boat?


Thanks

 

[mwph]

I am by no means an expert but it sounds to me like the engine was run far too long AFTER the impeller failed. Lots of boats out there to choose from. I say don't rush into it.

The vision of those melted parts may be etched into the back of your mind if you do buy the boat. Keeping you from fully enjoying the boat.

 

[hmonarch]

I had an imperller fail on an OMC. In my case, the failure was in the drive shaft that connected to the impeller. The shaft broke so no water was moving through outdrive to the engine. Since the water temperature probe had no water surrounding it, the probe didn't begin to register higher than normal engine temps until the engine block itself was so hot that the heat from the block heated the probe from the outside. As the engine coughed to a stop, I watched the temperature gauge go from 160 degrees to the peg at 220 in three or four seconds. The damage to rubber seals and gaskets in the heads, intake mainfold and exhaust manifold was extensive. The paint on the block blistered and pealed. I replaced the damaged seals and gaskets, had the heads milled and did a valve job. It took me about 10 days to do the repairs and I was back on the water. I used the boat for ten years after that without any engine problems.

 

[oaktree]

If one maintains their boat to extremes like I do and checks for raw water flow before venturing out, these meltdowns will not occur. I have only had to change my impellers one time due to failure of a fin and I could detect it by understanding the water flow before leaving the dock.

 

[Newbie]

If one maintains their boat to extremes like I do and checks for raw water flow before venturing out, these meltdowns will not occur. I have only had to change my impellers one time due to failure of a fin and I could detect it by understanding the water flow before leaving the dock.

Because nothing EVER happens away from the dock... Wingturd??

What about the fact that the boat in question is an I/O boat? You can't hear water flow when its underwater unless, you have cool mods or something.

I say pass, there's too many boats out there without this kind of history.

 

[BonBini]

Anatomy of a overheated engine: Your cruising along under load and life is good. As coolant temps rise to critical the piston continues to expand and will actually start to square up. As the failure continues, skirt scuffing followed by permant out of round wrist pin bores. Next pending on how well the condition and clamping force, the head gasket fire ring weakens then blows. Power is falling off, cylinder temps continue to rise, the piston continues to square up and a 4 corner seizure starts until the engine is stuck. After it cools it may restart for a bit but by now metal pealed off the cylinder walls has entered the lubrication system and this engine is "rip" done.

Your engine in question is some where in the above time line. At a minimum it could have some tight wrist pins. When the engine is cold, if you listen carefully you will hear a slight hollow knocking sound from piston skirt slap. As the alum piston slug heats up, the wrist pin bore will let go of the pin and the knock goes away. ... If this engine is using more oil than expected, then its probably a little farther along the time line.

That’s just what I can tell you about the internals. As far as the externals like the exhaust systems rubber parts and all that. I would think with no water going through the heated exhaust would melt any rubber pretty fast.

IMHO: I think this engine will have an early head gasket failure and the deal needs to be priced accordingly. Cheers to all... Ron

 

[comsnark]

What BonBini says makes sense to me.

My boat has I/O's. I have had the raw water pump (not the impeller) fail catastrophically on both engines, about 50 hours apart. By catastrophically, I mean in one case the drive pully started to wobble and the S-belt was came off. In the other case. . .a loud "bang" was heard as the pully came off the pump and hit the engine hatch.

In both cases, the engine overheated (quickly) and was shut down after a few moments. In both cases, there was no other damage to the engine, the paint is fine, and the boat actually runs better now than when I bought it.

What I am saying is as follows: A failed impeller is no big deal, and would not stop me from buying a boat. Running an engine after it overheats is a big deal. This boat has both conditions. I would be very, very cautious.

BTW and off topic: On a single engine boat, with an overheated engine; there can be hard decisions made once the sun starts to set and the crew starts to whine. I can see how this happens. With my incidents, I still had a functional engine after I shut down the one needing repair.

 

[JediJD]

Poacherz, how many hours on the boat? Abuse (intentional or otherwise) will tend to shorten the life cycle, but every engine has an inherent finite non-zero failure rate anyway. I would have a good idea of the cost for substantial engine repairs, apply a probability to it, and make that a factor in my purchase decision. At some number, the boat is worth it even if the engine is completely failing.

 

[my3sons]

Poacherz,

Your question of concern for damage and reliability is valid. I would be concerned.
Hopefuly the engine oil has some hours on it and an oil analysis will provide the information needed to make a decision. If so, make an offer subject to an acceptable full survey if you like. If the survey turns up bad news, walk away or adjust the offer accordingly.
I agree with the last post that if the deal is right, and you don't mind having to possibly put a motor in it down the line, why not go for it?
If you think you might not want to mess with it, let it go.

 

[gerryb]

I would pass on this one. Overheating of an engine is one of the lead causes for other internal mechanical failure such as a thrown rod or valve. Alternatively, I would agree with prior posts in that if I really liked the boat, I would go ahead and just assume a new engine will need to be installed at some point in the near future and take that into consideration when negotiating price.

 

[poacherz]

Many thanks to you all for your insight and guidance. Much appreciated.

Based on all your comments we decided to not make an offer on this boat and passed it over. Just didn't want to take the risk as we have no idea how long the motor was run after the overheat.

On the good news front, we made an offer on another 220 today with a clean history which was accepted. Hope to be the proud owner of a 220 by next weekend.:smt038

Thanks again..