Did the marina wreck my engine?

[Joe from ny]

Greetings all - I just recently started up my 1995 Larson with twin 5.0 Mercruisers for the first time this season. After about 5 minutes away from the dock, which followed a 10 minute warm up period at the dock, i notice the starboard RPM gauge needle drop a bit, and I heard a loud knocking in the starboard engine. I shut down, and checked around for leaks, checked oil level, etc..., all seemed fine. I started back up and heard the loud engine knock again, like a piston slapping. I shut it down and I finished on to my destination on the port engine alone, although it was a pain to steer due to the power steering pump being on the shut down engine.

When my yard looks at it they say the main bearing, or lower bearing is shot and the piston rod is hitting the cylinder. It needs to be replaced with a rebuilt motor, for a total cost of about $7,000.
Last season they removed the starboard engine to put a new flywheel and new starter, and removed and replaced the oil pan due to rusting issues. I used it for three months after that job with no problem.

My question is - could anything that they did during that job last year cause the bearing to go? Or could anything they did wrong during winterization have caused it? They have screwed up so many minor jobs on my boat in the last two seasons, causing multiple comebacks to correct, including improperly winterizing some waste hoses and a transom shower wand that then needed replacing.

Also, does that price for an engine replacement on this boat seem about right for the New York ?

In addition, could I run it like that with he loud knock till it dies, since I am replacing it anyway, or could there be a catastrophic failure that might be dangerous to the boat out on the water.

Thanks for your advice.


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[Mycroft]

The first thing you need, IMO, is a second opinion from a different mechanic/shop.

[Joe from ny]

Yes, I have a call in now to get that done. That being said, I am curious if their possibly improper service last season, and winterization this past winter, can cause my symptoms.


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[Cheechako]

Is it possible the flywheel they replaced has loosened? It does seem pretty coincidental.
You can get that 5.0 litre (chevy?) engine, a total rebuilt long block for about $1600 from Jasper last I checked.
The question is.... is the remaining $5000+ a reasonable price for installation?

[autumnbreeze27]

Originally Posted by Joe from ny

Last season they removed the starboard engine to put a new flywheel and new starter, and removed and replaced the oil pan due to rusting issues. I used it for three months after that job with no problem.

It's hard to say without knowing how many hours you put on the engine in 3 months, but assuming you used the boat frequently, seems like if there was a problem with reassembly it would have showed up here.

Originally Posted by Joe from ny

They have screwed up so many minor jobs on my boat in the last two seasons, causing multiple comebacks to correct, including improperly winterizing some waste hoses and a transom shower wand that then needed replacing.

You should get another mechanic to look at it and give you an estimate. These guys don't sound competent.

Originally Posted by Joe from ny

In addition, could I run it like that with he loud knock till it dies, since I am replacing it anyway, or could there be a catastrophic failure that might be dangerous to the boat out on the water.

I wouldn't do this.

[MarkSF]

Oil starvation might damage a main bearing, or serious overheating. Are you scrupulous about maintaining oil level, regular changes, quality oil, etc? Any history of overheating?

I suppose something they did while changing the pan might have caused oil starvation. Blocked strainer? Insufficient oil level? Unfortunately, you let them do the diagnosis - so you have no chance of proving they were at fault.

If the diagnosis is right, and the noise is the piston rod hitting the cylinder wall, the engine has a very short time to live, minutes probably, and there'll be a catastrophic failure. I've seen piston rods sticking out through the side of a cylinder block. At this point all the oil will be sprayed out, possibly causing a fire.

[LakeSuperior]

We blew up the star'b engine on my Bertram first run of the season this year. Threw a rod through both sides of the oil pan. Lots of oil smoke, no fire. It took about one minute from noticing an elevated noise level, knocking, to total destruction.

Long block on the 454 Gen IV was $4000 delivered. It took 6 hours to disconnect from the boat. Had to put the boat in the slings and then get a boom truck to inch it out. Another 8 hours to take off the good parts and clean them up including scrapping off old gaskets. Another 10 plus hours to reassemble long block.

Had the Bertram in the slings last night and new engine on the boom truck. When putting the remote oil filter adapter on found a configuration change on the block, show stopper. Two more hours to undo and put Bertram back on the trailer.

Short answer is $7000.00 does not seem bad if you get folks that know what they are doing and, most important, will warrantee the job. We still have 6 hours left to connect the engine when it is back in the boat, get it started and timed, and the shaft aligned. Plus it is not fun working on an engine once it is in the boat. Ask anyone.

[marlinmike]

A flywheel replacement is not taking out a main bearing, in addition $7000 sounds pretty high to me.

[Cheechako]

My guess is they are guessing at what is wrong... unless they have taken it apart....

[LakeSuperior]

Originally Posted by Cheechako

My guess is they are guessing at what is wrong... unless they have taken it apart....

Educated guess would be my guess. Additionally, the symptoms sound the same as in my case 60 seconds before the rod went through the oil pan at 3000 rpm full cruise load.

[jeepbluetj]

To me, $7K sounds reasonable. I've had 2 friends repower:
1. Mercruiser (chevy 350) - $6K, and this friend works for the boatyard, so that's the 'good deal' price
2. Volvo (chevy 454) - $5K in Arizona. Would have been $9K out here on the coast.

[Bill Seal]

Main bearing or big end bearing?
How can a rod hit the cylinder unless the piston has disintegrated?
Maybe something has gone through the intake?
Maybe a valve stem has seized and the valve is hitting the piston.
Yep; sounds like they're guessing. Stick a borescope in and have a look-see. Of course, in a boat you can't just get on a creeper, drop the pan and check out the bottom end.

[MarkSF]

And if you're really lucky, you'll find the smoking gun - a shop rag that they left in when they changed the sump, blocking the oil pickup strainer. Well, stranger things have happened!

[Joe from ny]

I know the boat is old, but other than that, the boat is mint for its age. The prior (original) owner was an anal, old geezer about 78 years old. He took great care of it, he would probably die if he saw how I keep it. The surveyor said it was in great shape for its age. I figure I can't get a 29 foot boat for the money that a reman engine job cost. Even if I eventually have to do two. The electric head and hot water tank are new. Years back it had the aluminum gas tank replaced under a recall. It is in pretty good shape as far as everything else goes. But I am probably looking to change marinas. They screw up too much on most jobs they do. Last year, they even pumped a few gallons of fuel into my waste tank when i asked for a pump out while filling up at the gas dock. I told the guy " what the hell you doing, I don't have two tanks!" He switched over to the pump out hose and sucked out the fuel, but i lost even more confidence in their service. Does anyone have an opinion on Lighthouse marina in jamesport. I am thinking of switching to them.

[guyfromiowa]

To answer the question, "How could a piston be hitting anything?" It's like this,normally the piston will be flush with the top of the block at top dead center position. The head gasket is likely compressed to about fifty one-thousandths of an inch. When the connecting rod bearing is loose the piston gets 'tossed' up the bore by the crankshaft, but instead of the connecting rod pulling it back down the bore the piston hits the inside of the cylinder head. At just the right engine speed and load you can clearly hear the noises at the bottom end ans well as the noises from the top end using a stethoscope. With an engine this old you will find a lot of worn parts inside that might have nothing to do with this failure. No cheap fix for this one.