1986 Force 125 lower unit issue

[baseshakers]

I have a 1986 Force 125. It had trouble shifting into gear (lots of ratcheting) so I machined the dog and gear faces square. At first this repair did wonders, but then it started kicking out of gear every 5 seconds or so in forward. If I adjust it far enough to get it tightly into forward I cannot get it into reverse, and if I adjust it far enough to get into reverse it won't shift into forward. The dog and gears are still square. The prop shaft has about 1/8" of in and out play. Any suggestions? Not sure what the next step is to fix the problem. Thanks everyone!

 

[jerryjerry05]

When you cut down the dog.
Did you cut the top of the dog or just the edge ?

There is a tiny yoke on the shaft.
It needs to be square and no wear on either side.

The shift shaft under the bottom carb is for adjusting if the other adjustments aren't working.

The shift cable: how old? hard to shift by hand?
​Loosen it and see if it can be shifted easily?

Pics of the internal parts.
​You didn't leave the F gear spacer out?

 

[baseshakers]

Hey Jerry thanks for the help. Answers below:

When you cut down the dog.
Did you cut the top of the dog or just the edge ?
Just the edge, the height of the dog is the same.

There is a tiny yoke on the shaft.
It needs to be square and no wear on either side.
Do you have pics of a good/bad yoke? There was nothing obvious but I will disassemble to check.

The shift shaft under the bottom carb is for adjusting if the other adjustments aren't working.
Will that increase the throw of the linkage at all? I was turning the shift rod (that goes into the lower unit) a half turn at a time. Will that change the mechanism differently from the shift shaft under the bottom of the carb? That one is just a PIA to access.

The shift cable: how old? hard to shift by hand?
Original from '86 as far as I know. It shifts pretty easily, but I have nothing to compare it to.

Loosen it and see if it can be shifted easily?
By loosen, do you mean disconnect from the motor?

Pics of the internal parts.
Will do when I disassemble.

You didn't leave the F gear spacer out?
Do you mean #28 in this pics? Almost 100% sure I put it back in when reassembling.

 

[baseshakers]

Hey Jerry thanks for the help. Answers below:

When you cut down the dog.
Did you cut the top of the dog or just the edge ?
Just the edge, the height of the dog is the same.

There is a tiny yoke on the shaft.
It needs to be square and no wear on either side.
Do you have pics of a good/bad yoke? There was nothing obvious but I will disassemble to check.

The shift shaft under the bottom carb is for adjusting if the other adjustments aren't working.
Will that increase the throw of the linkage at all? I was turning the shift rod (that goes into the lower unit) a half turn at a time. Is that different from the shift shaft under the bottom of the carb? That one is just a PIA to access.

The shift cable: how old? hard to shift by hand?
Original from '86 as far as I know. It shifts pretty easily, but I have nothing to compare it to.

Loosen it and see if it can be shifted easily?
By loosen, do you mean disconnect from the motor?

Pics of the internal parts.
Will do when I disassemble.

You didn't leave the F gear spacer out?
Do you mean #28 in this pics? Almost 100% sure I put it back in when reassembling.

 

[jerryjerry05]

Yes #28
​The yoke surfaces need to be smooth .

​It's a real pain to adjust the shift rod.
​Try removing the air intake cover.
4 tiny screws and the cover comes out and much easier to access.

Yes disconnect from the pin on the motor.

 

[baseshakers]

I finally had some time to tear into the lower unit, more answers below:

There is a tiny yoke on the shaft.
It needs to be square and no wear on either side.
Pics of the yoke:



Loosen it and see if it can be shifted easily?
The shift cable shifted very smoothly when disconnected from the motor.

Pics of the internal parts.


That pic is the forward gear. Reverse was just as crisp.
The dogs and gears were remachined and sharp when I reinstalled ~100 hours of operation ago.

You didn't leave the F gear spacer out?
It was definitively in there when I disassembled.

The prop shaft had a bit of travel in and out; is this normal? (pics of the in and out positions)