Catastrophic Engine mount failure

[JeremyH]

I have a 1986 S2 9.2C w/ 18hp Yanmar.

Coming in the slip Sunday...running ~800 rpm...I put her in reverse and all hell broke out. After being towed in, I realized the engine had broke free of all 4 engine mounts, sheared the connection between the engine and the shaft, and did significant damage to the through-hole. Fortunately shaft is still true and cutlass bearing is undamaged (albeit probably ready for replacement).

Replaced the engine mounts, but need to ensure the packing seal around the shaft is good before I re-splash her.

My questions:

1) anyone have the engine model number for the above S/V in order to order a service manual?

2) anyone have a online source for ordering said manual?

3) anyone EVER heard of such a catastrophic failure?

any help would be GREATLY appreciated

 

[Bron]

Send me email addresss and I can pdf you the owners manual for a Yanmar 2 GM

What caused the failure???

I have a 1986 S2 9.2C w/ 18hp Yanmar.

Coming in the slip Sunday...running ~800 rpm...I put her in reverse and all hell broke out. After being towed in, I realized the engine had broke free of all 4 engine mounts, sheared the connection between the engine and the shaft, and did significant damage to the through-hole. Fortunately shaft is still true and cutlass bearing is undamaged (albeit probably ready for replacement).

Replaced the engine mounts, but need to ensure the packing seal around the shaft is good before I re-splash her.

My questions:

1) anyone have the engine model number for the above S/V in order to order a service manual?

2) anyone have a online source for ordering said manual?

3) anyone EVER heard of such a catastrophic failure?

any help would be GREATLY appreciated[/quote]

 

[JeremyH]

My email is jeremyshardy@yahoo.com

Any help would be extremely appreciated. I'm at a Marina that doesn't haul out sailboats, nor has appropriate facilities for them. We hauled her out with a motor boat forklift and have use every jackstand they have to keep her on the hard while I glass over the cracks.

As for what caused the failure...I have no idea. I did find that the aft/inboard motor mount was mounted to the block, but not bolted into the stringer. It's a miracle that it didn't fail before. The 3 mounts that were bolted down all failed catastrophically...the top of the mount ripped from the bottom and the rubber absorbers were disintegrated. Moreover, all 3 of the mounted bolts pulled out of the stringer. The mounts that were bolted in were bolted w/ 1/2" x 1 1/2" lag bolts!!! Replaced the mounts and bolted them in with 5/8" x 3 1/2" lag bolts and poured West System into the pilot holes before driving them in...if it failes again, it'll rip the stringers right out of the engine compartment!

I've had "Nauti Angel" for almost 2 years and sail her every weekend...I'm just grateful it failed just outside my slip and not out on the water. My wife and I swam her to the shallows until we could find a forklift...

 

[Calypso]

Never heard of that. I did replace one mount that the rubber had collapsed and at idle the metal parts were banging on each other. I should do the others. I believe I have 3 inch lags. Sure don't think 1 1l2. I could imagine mounts on one side failing then motor would jump around and destroy the others. They don't last forever, even though I was hoping they would. Guess I'll be buying three mounts... mack boring or torrenson marine might have the manual. My boat had it included in the sale. What cracked in the hull? The stern tube? Did the lags fall out and into the bilge? I found scredriver handles down there- the metal dissappeared over the years from salt!

 

[Calypso]

The mount that was not bolted, was it on the side that would want to lift from the engine turning in reverse? If so then you had one mount holding that side down in reverse. Over time that mount got a helluva workout. Couple that with some oil contamination on the rubber, I can see how that could happen. My two cents.