90hp tower ss# 5031148 1978 I think slide clutch

[stevehendo34]

Can you pull the drive shaft and carrier without removing the lower unit or will you break something to do with shifting.
I cant figure out what moves slide clutch back towards the reverse gear or into neutral.
Any help extremely appreciated.

 

[Texasmark]

The prop shaft has a movable, spring loaded, (geared on the F end, cogs on the R end) "clutch dog" that shuttles between no contact or contact with the rear sawtoothed teeth of F or the front slots of R. There is a slot in the shaft and a pin through the dog which radially locks it to the prop shaft and the shifter moves it back and forth to select your gear.....aka which direction the prop shaft will rotate. the F and R gear are locked to the drive shaft pinion and turn constantly while the engine is operating.

Movement of the dog up and down the prop shaft is via a cam follower, a pointed tube with a spring inside which pushes against the dog. The shifting mechanism (via the shift shaft at the front top of the LU) is a twisting movement where a 3 detent cam is positioned with respect to the cam follower with each detent a different depth....F is deepest, N midway, R shallowest. Deeper the cutout in the cam the less pressure on the dog and it is positioned accordingly to select the desired gear.

The carrier nut will be your big headache due to corrosion. Then pulling the prop shaft because the rear shaft bearing carrier, which houses the shaft seals is oring fitted but usually corrodes to the LU housing. The prop shaft will come out with the bearing carrier mentioned, R gear, the clutch dog, and the cam follower. F gear remains in the lower unit as is the shifter cam which is locked in place via the shift shaft protruding through it.

 

[stevehendo34]

Very nice: In my mind could not see how the clutch dog moved on the shaft during shift, but I looked in there and saw how the shift cam turned/changed when shifting forward, neutral and reverse.

The one thing I can't seem to understand how my cam follower that sits in the hole on the end of the shaft has nothing under it The book says there are three small balls--not in mine and no spring and or guide. I wonder if I lost my spring and or guide block when I took out the cam follower from the shaft, or the spring and guide block are in clutch dog, or mine dose not have them? Note: I did not remove clutch dog from shaft.

Anyway THANKS, you expiation helped a lot after reading it and looking in the motor I can see whats going on.

Note: for others use:
1. I removed carrier nut with BF punch and BF Hammer
2 Put two 3/4 inch hard would flooring between lower unit and Prop--this leaves a 3/4 inch gap between carrier and lower unit case.
3 put nut on shaft on top of prop.
4 turned the nut and it started the carrier off easily the first 3/4 of an inch.
5 then I moved the wood out even farther on the diameter of the lower unit case and moved carrier some more turning prop nut.
6 by that time it came fight out after tapping the prop shaft back and forth.

Note: I noticed the prop shaft was bent slightly, (May have helped cause leak), My engine rebuild place has a machine to measure and bend crankshafts. Mine was quite bad, (30 thousands), he bent it back to 3 thousands end to end with his machine.

What an adventure, now to put it all back to with new prop shaft seals, my original mission.

 

[Texasmark]

Very nice: In my mind could not see how the clutch dog moved on the shaft during shift, but I looked in there and saw how the shift cam turned/changed when shifting forward, neutral and reverse.

The one thing I can't seem to understand how my cam follower that sits in the hole on the end of the shaft has nothing under it

there is a sideways (L to R ) slot cut into the front of the LU casting and the cam slides horizontally into that slot. It has a splined hole in it. The shift shaft goes down into the LU and through a boss then through the cam and stops in a second boss.

The book says there are three small balls--not in mine and no spring and or guide.

You have to pull the spring out from around the dog and pull the pin. then all that stuff will come out. The balls are behind or in front of, forget which....been awhile, the spring. My opinion of having the balls was a tweak on how much spring pressure was needed to make the thing work. Seems once they got it working they never upgraded the design with the right spring and left the balls out.....course if it works, don't fix it.

I wonder if I lost my spring and or guide block when I took out the cam follower from the shaft, or the spring and guide block are in clutch dog, or mine dose not have them? Note: I did not remove clutch dog from shaft.

Anyway THANKS, you expiation helped a lot after reading it and looking in the motor I can see whats going on.

Note: for others use:
1. I removed carrier nut with BF punch and BF Hammer
2 Put two 3/4 inch hard would flooring between lower unit and Prop--this leaves a 3/4 inch gap between carrier and lower unit case.
3 put nut on shaft on top of prop.
4 turned the nut and it started the carrier off easily the first 3/4 of an inch.
5 then I moved the wood out even farther on the diameter of the lower unit case and moved carrier some more turning prop nut.
6 by that time it came fight out after tapping the prop shaft back and forth.

Note: I noticed the prop shaft was bent slightly, (May have helped cause leak), My engine rebuild place has a machine to measure and bend crankshafts. Mine was quite bad, (30 thousands), he bent it back to 3 thousands end to end with his machine.

What an adventure, now to put it all back to with new prop shaft seals, my original mission.
2 seals back to back on the prop shaft. One seals oil in and the other seals water out. Sounds like you'll have her going in no time.

Look in your quote for my answers.