Transom Plate Assesment

[NZ-Kevin]

I have an early MC-1 drive, which I've been having problems with. Finally got the bell housing off to remove the stuck driveshaft. The clip holding the bearing in wasn't even there, so I pulled the shaft out with a slide hammer, but it left the bearing stuck in anyway. I'll need to get a puller for that. That's just the background, my question is about the transom plate. The round boss that the drive belows go round (with the bearing in the middle) is badly corroded. At the bottom, so I presume water has stood in it. The bearing clip groove is partly missing, but only at the bottom. How much damage here is tolerable, and what, if any, are the potential future issues this could cause me?

 

[Pete104]

Re: Transom Plate Assesment

It don't sound good. Can you post a pic?

 

[NZ-Kevin]

Re: Transom Plate Assesment

OK, can I just insert an image into the post -is there a maximum size for the image?

 

[Don S]

Re: Transom Plate Assesment

http://forums.iboats.com/showthread.php?t=468676

 

[NZ-Kevin]

Re: Transom Plate Assesment

It doesn't look too good either, here are a couple of pics. it's a bit shiny as I sprayed soem WD40 to get rid of the muck.

 

[Don S]

Re: Transom Plate Assesment

You need a new transom shield. That missing section is also the surface the bellows attaches to in order to seal water out.

 

[NZ-Kevin]

Re: Transom Plate Assesment

I had a bad feeling that might be the case, but I was trying to avoid it. It will have to be a complete secondhand Alpha unit, which means mods to the transom to fit it, and a new bell housing on the motor. All means many $$$ before you all say I can pick one up for few$ I'm in New Zealand and Mercruiser spares are thin on the ground here.

 

[achris]

Re: Transom Plate Assesment

I had a bad feeling that might be the case, but I was trying to avoid it. It will have to be a complete secondhand Alpha unit, which means mods to the transom to fit it, and a new bell housing on the motor. All means many $$$ before you all say I can pick one up for few$ I'm in New Zealand and Mercruiser spares are thin on the ground here.

The mods to the transom are minor. My original engine was 1972, replaced in 1994 with a Gen II. Just a shave off the inside of the cut-out and a couple of new holes drilled at the top. Real easy. The new flywheel cover shouldn't be too much drama either. Get a second-hand one from the US. Plenty of on-line sites, and freight charges aren't too bad...

 

[Don S]

Re: Transom Plate Assesment

There is an alternative to replacing the gimbal housing you may want to look at. http://www.ghrkits.com/index.html

I've never used one, and I don't know anything about the kit, or if you can even replace the bellows after the kit is installed. If it is a temporary fix and you can't replace the bellows, at least it gives you a few years to find a new housing.

 

[NZ-Kevin]

Re: Transom Plate Assesment

That's an interesting product Don. One of my thoughts was to drill and tap some holes and fit some smal pins as anchors then build up the missing material wit a metal loaded epoxy. This product does a similar thing, I think the PVC sleeve acts as a mould. The transom plate might not be scrap after all.

 

[fishrdan]

Re: Transom Plate Assesment

OK, I know I'm going to get beat-up, slammed and hammered on this one (be kind...) but the transom shield on my 72 MC-1 looks worse than that one and the bellows fit OK.

15 or so years ago the PO of my boat took it in to have the drive rebuild, Ujoints let go too, and it thrashed the rim that the Ujoint bellows mount to. The lip was almost all gone. The shop (which is pretty reputable around here, not saying it was the right call) advised my buddy they could replace the transom shield for $$$$$, or just knock the rest of the lip off and mount the bellows further back. $$$$$ wasn't in his budget so they knocked that lip off and mounted the bellows to what was left. There was plenty of unobstructed outer bore to mount the bellows.

I never had a problem with the bellows leaking at that connection and have replaced them a couple times since then, never having the bellows leak at the transom shield connection. (I once had the bellows split after 6 year, but that was owner neglect.....) I'm not saying this is the proper way to do the repair, but it has worked OK on my MC-1 drive. The only thing that's off is the bellows stretch a bit further (maybe 3/4"?) than they are supposed to, but they have never leaked from the transom shield connection. I always make sure to use a liberal amount of bellows adhesive since this is not the intended location for the bellows to mount, but it has worked fine.

Before even thinking of doing this, make sure the mounting surface for the bellows will allow the bellows to fit further back, after the lip is knocked off. I'm pretty sure the newer transom shields won't allow this as there are "bellows stops" (for lack of a better term) cast into the housing, that would interfere with the bellows sliding further back.

I tried to find a pic of my beat-up transom shield, in my plethora of pics, but couldn't find one.

OK, let'er fly.......

 

[fishrdan]

Re: Transom Plate Assesment

^^^ one thing I should add. The bellows have a ridge inside (mates with valley on transom shield) that should be trimmed off if making this hodge-podge repair. "Carefully", slice the ridge off with a razor blade so the bellows are smooth inside, ridge is gone, but no gouges. If this ridge is left on, the clamp might not squeeze the bellows tight enough and create a gap in the sealing surface, not 100% contact between the bellows and housing.

 

[NZ-Kevin]

Re: Transom Plate Assesment

Thanks for the advice all. Given the amount of problems on the unit I think the only real solution is to replace the whole thing with a newer Alpha drive. Even secondhand thats way beyond my budget so I'll just have to do my fishing from the shore.