Martin 75TS won’t run in “forward”

[hiram1914]

Started up my Martin 75TS this morning. It started quickly and idled down well, amazing since it had been at least 3 years since its last outing. After it idled awhile I shifted into “forward,” there was a sound like gears clashing and the motor stalled. I put it back into neutral and it started immediately, but any attempt to put it in “forward” caused the gear clashing noise and an immediate stall. If I attempt to start it “in gear” it behaves as though the motor is seized. Any suggestions???

[Buccaneer]

I wonder if the “friction clutch” is seized up some how?

Prepare to be boarded!

[hiram1914]

Possibly, but when I disconnected the cable from the clutch, there’s still plenty of resistance coming from… ????

[frankr]

Gut reaction is something is seized in the lower unit, below the clutch or lower. Or bird’s nest of fish line behind prop???

[The Boat House]

• This reply was modified 4 years ago by The Boat House.

[hiram1914]

You’ve given me something to do on this rainy, overcast day, not that I wanted the work. I’ll tear off the foot and see what’s there!

[hiram1914]

It was a dark and stormy morning… but I tore into the lower unit of the 75TS and discovered that the lower driveshaft was “corroded in place.” Although I religiously (every Easter) refill the lower unit it appears that the last time I used the motor water got into the lower unit and forced out some of the lubricant. The motor was left idle for 3+ years, enough time for corrosion to work its evils. Fortunately, I had a spare lower unit so I swapped it for the old one. Now I’m soaking the original lower unit hoping it can be repaired.

Thanks for all the help, especially you, Tubs, for the great photos. They helped.

[hiram1914]

Update: I decided to take another look at the seized lower unit after several hours of soaking It turns out that there was NOT any corrosion that I can find in the lower unit excepting on the large spring between the two driveshafts and it was easily removed. With the pinion removed the ring gear rotated freely and the driveshaft (without the pinion) did, as well. When the unit is reassembled, though, the unit jams and can’t be turned in either direction. The teeth looked good, but I didn’t really study them. Another look is definitely in my future.

[jp53-n]

I’ve got two gear cases for those engines if need be.

[The Boat House]

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