Replacing Transmission

[Alansails]

Great Job Jim, you are ALOT more courageous than I am, I assume the boat was out of the water?
what made the transmission go bad? salt water?, many hours? bad design? just curious.

 

[c130king]

Nope. Boat was in the water in the slip the whole time.

My understanding, from the other guys, is that the damper plate assembly is a bad design and allows the transmission shaft to to rattle inside the damper plate which wears out the teeth/splines (not sure what the correct terminology is) of the transmission shaft and the collar inside the damper plate.

Salt water had nothing to do with it.

Motor has 2000 hours.

Cheers,
Jim

 

[Witzend]

I believe the main enemy here is idling your engine. Because we only have a three cylinder light weight engine, each time the engine fires, the light weight flywheel accelerates. This loads up the leading edge of the interface between the input spline shaft of the transmission and the collar of the damper plate. Then, between the time the next cylinder fires (a greater period of time when idling) the engine slows down, but because of the momentum of the input mechanism of the turning transmission in neutral, this now switches the loading point to the trailing edge of the interface.
Once some play starts to develop within this interface, the wear action increases until failure occurs.
If the interface is loaded (in gear and pushing water) than the switching back and forth of the loading point does not happen, because there is more resistance within the system.
The stiffer design of the R&D damper plate, only exasperates this problem. This is one of the reasons I chose to use the proper torque rated damper plate, which is softer and provides more torsional noise isolation, not allowing the full acceleration to reach the interface each time the engine fires.
Bottom line,
DON'T IDLE YOUR ENGINE IN NEUTRAL TO CHARGE YOUR BATTERIES!!!