Transmission failure

[Noah]

If you go for that transmission you might as well shorten your shaft at the same time. Minimal added cost and would also be an opportunity to inspect, polish and true. Ideally the prop should be 1in. behind the strut.

[KWKloeber]

Dh

What are the particulars - model # or MPS item # etc?

[dhagen]

It is a Baysan BMT-M30-2.00.  If I have the shaft shortened, I would have to have the boat hauled, which I don't want to do at this point.  Maybe when It is hauled for the winter.

[Dave DeAre]

I replaced the transmission on my 2002. Yes, the aft cabin must be empty, the "box" can be easily removed with 4 or 6 screws. Coupling disconnected and the shaft pushed back for clearance. Linkage disconnected and then the transmission bolts are accessed with a socket wrench and extension. Job is easy, unless any fasteners are corroded or frozen. It probably took me 4 hours total to do the job. Replace the damper at the same time.

[Ron Hill]

dhagen : Rule of thumb - the prop distance from the strut should be one shaft diameter (1")

A thought

[Bill Shreeves]

dhag, I replaced my damper plate, tranny (actually a gearbox not a tranny I'm told), coupling, stuffing box, cutlass prop & shaft myself a few years ago.  The gearbox wasn't that hard.  Most everyone will tell you to always replace the damper plate when you remove the gearbox.  The cost will likely be all parts because it takes little time to actually replace and I'd highly recommend it while they're in there.  Also expect to pay labor for aligning the engine. If the gearbox is only longer and not lower there shouldn't be much if it was reasonably aligned before.  If it hasn't been aligned in a long time it might take more time because the mounts settle over years I'm told.

[dhagen]

I removed the cabinetry yesterday. It was more than 4 screws, more like 8. The key trick is trying to figure out which eight!   And then getting at them through the opening in the top.

[dhagen]

It turns out the damper plate had broken into 3 pieces.  Replaced it and it is good to go.

[Jon W]

Several posts on damper plate problems lately. I'm wondering if this is a problem I need to start saving for. What causes the damper plate to fail, or break into multiple pieces? How many engine hours do you have? Thanks for the help.

[Ron Hill]

Guys : When I replaced the damper plate on my old M25XP, I did it as a "just in case" as I had everything out of the boat and was replacing the transmission (Hurth100). That old damper plate was working just fine.  That old engine had almost 5,000 hours on it!!

A thought

[Ron Hill]

Guys : You can shorten the shaft while the boat is in the water, BUT you are cutting away part or all of the keyway!!!

When I did that I had a flexible coupling and didn't use the keyway!

[dhagen]

My engine has about 1000 hours on it, but it is a 2001. My understanding is that on the M35B, it is just a piece of plastic. My guess is after 20 years, the plastic just got brittle and cracked.

[Ron Hill]

dha : No it is not just a piece of plastic!!
 
I'd describe it as an elastomeric connection that the shaft fits into.  On the M25/25XP engines it "looked" like a old clutch plate.
Maybe Ken or Mainsail can give a better description.

A thought