Merc 3.0 Harmonic Balancer Pulley Issue

[zdziarskih]

Good afternoon all.

I did a complete write-up on the timing chain cover oil leak fix last year on the forum (http://forums.iboats.com/forum/engin...=1472146868027) and I ran into a belt issue last weekend...

While at the dock, I started the boat and noticed the volt gauge was around 10 and immediately shut down the idling engine. Pulled the doghouse and found the v-belt was off the pulley's. I put the pulley back on and off I went. Went out about 3 minutes and noticed the gauge dropped to 10 again. At this point, I was at my house dock and pulled it in. I put the belt back on again, idled to the launch and decided to take it back to the house and have a look.

So, 2 things I noticed. The belt wasn't broke, but twisted, and wouldn't stay on the pulley's. The Harmonic Balancer pulley is now further away from the original position I had it in and is not inline which caused the belt to do what it did. Has anyone heard of this happening before? I would have assumed the pulley would stay in place... I did use the block of wood/hammer method to put it on but I wouldn't think that has anything to do with this issue...

Any thoughts? i am going to put it back in place with the hammer and wood again and see what happens I guess...

I did a ton of searching for a similar issue but came up empty


Thanks,
Harry

 

[Fishermark]

Your balancer could be coming apart. There is a rubber isolation ring that sometimes goes bad. May be time for a new balancer. Otherwise, I have never heard of the whole balancer coming out.

 

[Scott Danforth]

two things.

either the damper is coming apart, or the whole balancer is walking off the end of the crank due to a missing or busted crank snout bolt.

did you at any time attempt to turn the motor over with the crank snout bolt and a socket?

 

[Rick Stephens]

two things.

either the damper is coming apart, or the whole balancer is walking off the end of the crank due to a missing or busted crank snout bolt.

did you at any time attempt to turn the motor over with the crank snout bolt and a socket?

+1 on that.

Even if the rubber mounted outer ring is deteriorating and moving, that won't effect the pulley which is mounted to the inner solid portion of the balancer. More likely the bolt got loose or is damaged, like Scott mentions. You might pull that bolt out and inspect it and the threads inside. If in good shape use some blue threadlocker to keep it in place.

 

[zdziarskih]

Thanks all but I am confused about the snout bolt... if you look at the pictures I posted in my link, there is no bolt. When I pulled the pulley off, there was a key way, and the pulley. The puller pushed on the concave portion at the end of the crank shaft for removal. Am I missing something? I am heading out to the boat now to look around a bit before I dig in there to fix this...

Any help is appreciated


thanks,
harry

 

[Alumarine]

Some of the older 3.0's crank bolts.
The damper on them is a press fit.

I believe the GM part no, for it is 3826280

 

[zdziarskih]

After further review and reviewing many images, I believe I may have thought I had the pulley on far enough to line up with the water pump pulley and the alternator, but actually didn't . There is no way the pulley backed it's out... I am going to push the push the pulley on the shaft a bit more to line up with the others tonight. I will update with my results...

Thanks for everyone's help thus far...


Thanks,
Harry

 

[fishrdan]

The harmonic balancer should bottom out on the crankshaft, hitting it will make a different sound - when it bottoms out on the crank.

 

[alldodge]

Thanks all but I am confused about the snout bolt... if you look at the pictures I posted in my link, there is no bolt. When I pulled the pulley off, there was a key way, and the pulley. The puller pushed on the concave portion at the end of the crank shaft for removal. Am I missing something? I am heading out to the boat now to look around a bit before I dig in there to fix this...

Any help is appreciated


thanks,
harry

That would be the issue. The bolt would need to be removed before the damper was pulled off. If the bolt was not there you need to get one and the washer.

 

[Alumarine]

Some of the older 3.0's crank bolts.
The damper on them is a press fit.

I believe the GM part no, for it is 3826280

I just reread this and see I forgot some words.

It should read "Some of the older 3.0's don't have crank bolts or even threads for one."

 

[Rick Stephens]

I just reread this and see I forgot some words.

It should read "Some of the older 3.0's don't have crank bolts or even threads for one."

That is wild. Sure wish I knew those kinds of things. If was my motor I'd a figured it was messed up at the factory.

 

[Fishermark]

Here's the 3 liter I pulled out of my Wellcraft - note no crank bolt - and the pulley is integrated into the balancer. Not bolted on like is typical with balancers.

 

[Alumarine]

Here's the 3 liter I pulled out of my Wellcraft - note no crank bolt - and the pulley is integrated into the balancer. Not bolted on like is typical with balancers.

Both my 74 and 80 are like this. Neither have threads in the crank end.
I wonder when they switched?

 

[zdziarskih]

Yes, no bolt on my year, not sure of other years... I did push the pulley on another 1/4" or so and now it completely lines up with the other pulleys. I put a new belt on and had it out this past weekend with no issues at all. So just a recap, no crank shaft bolt, pulley wasn't pressed on far enough, it is now and all set.

Thanks everyone for your help with this... It was nerve racking for a bit there