Mercruiser 5.0 noise - video - what is it?

[Joe from ny]

1995 mercruiser 5.0 with about 630 hours. Had flywheel and starter replaced beginning of 2014 season. No problems that season. Boat went to marina at end of season for winterization and beginning of 2015 season had this noise upon first receiving boat back. I pulled each spark plug one at a time. No difference. Oil pressure is fine. Oil looks good. Boatyard claims it is main bearing and I need a rebuilt motor job at $7,500. Since they screwed up every other job I had them do I think they are wrong. What can it be? Check out the video. http://youtu.be/jhe9p3L2kxo

http://youtu.be/iAzgWnKb5_Q


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[paulajayne]

Sounds like a pulley bearing - take the belt off and restart it but not for long.

[Cheechako]

at the beginning of the first video it sounds like something external on the engine, as mentioned pulley or something? But later in that video and especially the 2nd video it almost sounds like a rocker arm or something. Either way it sounds pretty loud (maybe just the recording) but more like a rod bearing than a main bearing... if either. Stuck valve?

[Joe from ny]

Sorry, I forgot to mention in pursuit of elinating possible causes, I had both heads off and the valves done. So the heads, valves, springs, and head gasket are good now. And one guy I had look at it said maybe something on the flywheel worked its way loose and the noise comes from the bell housing at the rear. But I only had the issue this season, not last season after the flywheel was replaced.

[Joe from ny]

Originally Posted by paulajayne

Sounds like a pulley bearing - take the belt off and restart it but not for long.

I don't think it could be the pulley. The noise really sounds like it is coming from the back of the motor.


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[Cheechako]

Originally Posted by Joe from ny

Sorry, I forgot to mention in pursuit of elinating possible causes, I had both heads off and the valves done. So the heads, valves, springs, and head gasket are good now. And one guy I had look at it said maybe something on the flywheel worked its way loose and the noise comes from the bell housing at the rear. But I only had the issue this season, not last season after the flywheel was replaced.

If it sat all winter, still possible it stuck a valve, or bent a pushrod to the rocker... due to sitting and then start up. It is a funny clacking sound, not typical for engine internals to my ears anyway, they usually seem to be more of a knock but not so much a clatter. Anything else in the flywheel area on those? Coupling to the outdrive?

[Joe from ny]

I thought it might have been possible that something they did on the flywheel or starter job might have backed out or came loose and it bouncing around in the flywheel area. In neutral at low idle it is mostly quiet, but under throttle advance it becomes louder and more random, rather than a consistently timed noise.

[Cheechako]

Theres some kind of U joint/ CV joint etc between t he engine and the outdrive isn't there? Was it run with outdrive tilted up? I had 5.0 VP outdrive a couple years back.. cant remember how it's set up.
There are a lot better forums for this type of setup than this one though....

[Joe from ny]

Which forum?


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[Cheechako]

maybe try googling "Mercruiser forum". I googled Volvo Penta forum for mine and looked around. A lot of mechanics etc that work on those hang out there.


here's one: http://forums.iboats.com/forum/engin...ines-outdrives

[wmcruiser]

Check the main pulley ,the counter balance ring comes of a rattles.
If it is you can replace as its set to balance engine.

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[jimbunyard]

Originally Posted by Joe from ny

I thought it might have been possible that something they did on the flywheel or starter job might have backed out or came loose and it bouncing around in the flywheel area. In neutral at low idle it is mostly quiet, but under throttle advance it becomes louder and more random, rather than a consistently timed noise.

Seems like there are two sounds going on. The loud, sometimes intermittent clacking sounds like something is loose, and is rattling as it comes into the proper period to hit whatever it is that it's hitting. The only thing that comes to mind is item 10 shown in the diagram below, but even if that is it, you have to get to it to find out (and to repair it).


Of course that leaves out why it just suddenly occured after being in winter storage. Did someone from the marina drive the boat to you, or did you pick it up from them? The question being who did the initial startup after storage?

The other sound, which may be an artifact of the recording, is the lower frequency rattle/rumble present at all times in the video, a sound that I habitually equate with bottom end problems. That you have good oil pressure can indicate the bottom end is good, but not always. If you have thrust bearing issues (which could be associated with the first noise as well), the oil pressure can be fine.

There is a remote possibility that the engine coupler or starter (or even flywheel) could be loose or defective. Does it shift into forward and reverse without issues?

If you or a competent mechanic can't find out for sure what the noise is with the engine in place (but you should be able to), the engine has to come out. From the sound of it, and given the extremely limited access, I'd say it has to come out anyway. Once you get it out the engine is very easy to run on the ground and you'll be able to tell what's going on.

Given you've not been happy with the marinas' service, I'd find another mechanic. Mercruisers are probably the most common marine engine in the US, and for the most part are very easy to work on and troubleshoot; there is a good mechanic within shouting distance.

[Joe from ny]

Also I forgot to mention that I pulled each plug one at a time, no difference in sound. And the oil pressure is fine and the oil looks good on the dipstick.


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[Joe from ny]

Originally Posted by jimbunyard

Of course that leaves out why it just suddenly occured after being in winter storage. Did someone from the marina drive the boat to you, or did you pick it up from them? The question being who did the initial startup after storage?

They did the initial startup after service and storage. I got to the marina and it was already in my slip. I started it up for the first time this season in the beginning of July and warmed it up for a few minutes. I noticed the noise as soon as I was getting out of the canal into the bay.

Originally Posted by jimbunyard

There is a remote possibility that the engine coupler or starter (or even flywheel) could be loose or defective. Does it shift into forward and reverse without issues?

Yes, it shifts normally.

Originally Posted by jimbunyard

Given you've not been happy with the marinas' service, I'd find another mechanic. Mercruisers are probably the most common marine engine in the US, and for the most part are very easy to work on and troubleshoot; there is a good mechanic within shouting distance.

Finding a competent marina is proving to be harder than I thought it would be. I walked into another local marina to discuss my issue to see if I could bring the boat in for a listen. The service manager had the nerve to tell me with a straight face that that motor (carbed Mercruiser 5.0) is not available anymore rebuilt from anywhere. He said if I was really attached to the 1995 boat, he could replace both carbed motors with fuel injected motors for about $30,000! What total BS. They had no interest in even seeing if I actually needed another motor at all. How could they tell if the first marina's diagnosis was correct? Just tried to con me into spending 30 G's.
I am really disappointed with my experience there.


Can anyone recommend a mobile boat mechanic that would be local to Jamesport or Riverhead, who I could call to come out to check it out before I pull it out of the water soon for the season?



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[jeepbluetj]

Originally Posted by Joe from ny

Finding a competent marina is proving to be harder than I thought it would be. I walked into another local marina to discuss my issue to see if I could bring the boat in for a listen. The service manager had the nerve to tell me with a straight face that that motor (carbed Mercruiser 5.0) is not available anymore rebuilt from anywhere. He said if I was really attached to the 1995 boat, he could replace both carbed motors with fuel injected motors for about $30,000! What total BS. They had no interest in even seeing if I actually needed another motor at all. How could they tell if the first marina's diagnosis was correct? Just tried to con me into spending 30 G's.
I am really disappointed with my experience there.

That's pretty horrible. Since in 30 seconds I could find out that I can buy a long block marine 5.0 from summit for around $2K. Does the marina figure that nobody knows how to google?

Or DIY. That's what lots of folks end up having to do. (I've always been the DIY guy, but that's just me)