Yes, broken crankshaft. Now what? (was "Busted crankshaft?")

[superfets]

So i bought a trailer last week and it came with a boat on it. Picked it up from a couple young guys who admitted they new nothing. They said they saw it on the side of the road with a for sale sign. The seller told them all it needed was a starter. They found a starter, installed it. Then they said it cranked once or twice then the starter, just as they put it," freewheeled". They removed it in hopes of getting there money back. No luck there. Then tried to sell it. I agreed to buy from them for the value of the trailer. So i gave them some cash, got a receipt. picked up some insurance and dropped it off at my brothers place where i can work on it. And that's where we are now.

Onto the broken crankshaft. My first instinct was missing teeth on the flywheel. So after i dropped it off i quickly looked at the flywheel with a flashlight, seeing as the starter is not installed and in a box, it looked good,so i reached in there to feel it and i was able to move it back and forth a few inches by hand! The crankshaft pulley didn't move, it did feel a little rough i must say, and i haven't even taken the plugs out yet. Sorry now picture of the motor but it's a 1988 3.0 mercruiser with an alpha one outdrive i believe.

With this minimum amount of information and all of your combined wisdom, does anybody have a theory on what is going on?

I'm hoping to pull the engine next weekend to get to the bottom of this and i'll be sure to upload pictures and keep you all informed.

Thanks all.

 

[alldodge]

I think maybe the flywheel bolts either came off or the flywheel sheared off

 

[superfets]

That crossed my mind also. It will be interesting to see if your right.

 

[Bondo]

Ayuh,.... Quite likely,.... Pull the drive, 'n see if it gets looser without the driveshaft in the coupler,....

 

[Scott Danforth]

its a 3 beer job to pull the drive and get ready to lift the motor. you will need a tall cherry picker or make a gantry.

may be able to run the trailer on the hubs like I did once to allow my cherry picker to pull a 3.0

 

[Bt Doctur]

It just may be a cracked ring gear too

 

[superfets]

Ayuh,.... Quite likely,.... Pull the drive, 'n see if it gets looser without the driveshaft in the coupler,....

That's where i'm going to start. Thanks

 

[superfets]

its a 3 beer job to pull the drive and get ready to lift the motor. you will need a tall cherry picker or make a gantry.

may be able to run the trailer on the hubs like I did once to allow my cherry picker to pull a 3.0

Only 3 beers! Awesome. We'll have it ready by lunch then. I think were going to use the tractor bucket to lift the motor out.
Thanks

 

[superfets]

It just may be a cracked ring gear too

That's another possibility that i would be happy to deal with. You're all giving me hope that i can save this engine.

 

[achris]

Only 3 beers! Awesome. We'll have it ready by lunch then. I think were going to use the tractor bucket to lift the motor out.
Thanks

Pffft. Pulling the drive is a 6 minute job. 3 beers for me is about 6 months.... ;-)

 

[superfets]

Pffft. Pulling the drive is a 6 minute job. 3 beers for me is about 6 months.... ;-)[/QUOTE]

Ya, I agree it's a 6 minutes on the drive, probably 3 beers for wiring/cables/fuel line/exhaust/mounting bolts....ect. Ok, maybe 4 beers the first time around.

 

[Grub54891]

Before pulling the drive, Put it in fwd gear, This lines up the shift dog, if you don't, it will damage it, and make the drive hard to remove.

 

[superfets]

Before pulling the drive, Put it in fwd gear, This lines up the shift dog, if you don't, it will damage it, and make the drive hard to remove.

Yes, Drive in full forward. Thanks. That's great advice. I would hate to take 2 steps back before taking a forward one.

 

[superfets]

Anybody willing to share some wisdom on pulling the motor itself. A side from the aforementioned wires/hoses and such. I haven't had a good look at the engine mounts themselves yet. But do i leave the motor mounts on or off? Leave the back mount there and keep the front on the motor? What's this about alignment? I ordered a hard copy of the service manual but it won't be here for another week or two. Thanks again in advance for any advice.

 

[Bondo]

Ayuh,.... Pull the lag bolts outa the front mount, leavin' the mount on the motor,....
On the aft end are 2, 1/2" bolts holdin' the flywheel cover to the transom, remove those 2 bolts,...
Then lift straight up, 'n out,...
Install in the reverse order,...

 

[superfets]

Ayuh,.... Pull the lag bolts outa the front mount, leavin' the mount on the motor,....
On the aft end are 2, 1/2" bolts holdin' the flywheel cover to the transom, remove those 2 bolts,...
Then lift straight up, 'n out,...
Install in the reverse order,...

Awesome. Sounds pretty straight forward. Thanks

 

[Bondo]

Ayuh,... Boat motors are pretty Easy to work on, once ya get the hang of it,....

In my shop, pullin' yer motor is less than a 3 beer operation,....
Probably 20 minutes to 1/2 hour deal,....

 

[superfets]

Ayuh,... Boat motors are pretty Easy to work on, once ya get the hang of it,....

In my shop, pullin' yer motor is less than a 3 beer operation,....
Probably 20 minutes to 1/2 hour deal,....

Good to hear. Now I just can't wait to see what i find is the problem.

 

[achris]

Before pulling the drive, Put it in fwd gear, This lines up the shift dog, if you don't, it will damage it, and make the drive hard to remove.

No, it aligns the upper and intermediate shift shaft shoes to fwd/aft, so they slide apart. If you don't, you'll bend the shafts and/or shoes.

Chris.........

 

[Bt Doctur]

This will be useful too http://www.boatfix.com/merc/Install/gas/86017211.pdf