Did I pull the shift assist cylinder too far?

[Springcrik]

I was replacing the water pump on my 1977 Johnson 115, 20" shaft, with the dual tube water pump. I decided to put a new shift rod oring in the cover above the shift assist cylinder while I had it off. When I was pulling up on the cover, the shift rod kind of moved up with it, and the shift assist cylinder barrrel came up at the same time. The top of the cylinder barrel was about 1/4" below the surface of the lower gearcase before I saw what was happening and pushed it back down. Well, now the shift rod doesn't want to move up and down; it will only move about 1/4". It would move up and down with a click for forward, neutral, and reverse before this. I have tried to gently tap the barrel back down with a brass drift, but it feels pretty solid.
Did I pull the cylinder barrel up over the lower end of the assist piston, and allow the detent valve balls to pop out or what? Am I going to have to take the whole lower gearcase out to fix it?

 

[Joe Reeves]

Re: Did I pull the shift assist cylinder too far?

I've never heard of the shift assist assembly being able to travel upwards without having the propshaft being pulled outwards at the same time.

However, if when removing the shift assist cover, one should pull upwards on the shift rod instead of simply prying the cover up, I suspose it's possible to have something go out of place.

At any rate, that unit slides smoothly into place...... not a good idea to attampt to force it. If it were me, I'd dismantle the lower unit and start from scratch rather that to chance a expensive mistake.

If you should have damaged the shift assist assembly, I have a few left in stock.

 

[Springcrik]

Re: Did I pull the shift assist cylinder too far?

Thank you for the info. To help others from making this mistake, I wasn't pulling up on the shift rod; I was prying the cover up and the shift rod was sticking to the cover, and slid up with it. I'm pretty sure the lower end of the cylinder barrel slid up over the end of the piston seal, and now unless I can realign it, and guide the barrel back over the lower piston, I'm going to learn more about lower units than I really wanted to know. I will post back with what I find after I tear it down.
I will holler at you if anything tore up.

 

[ezeke]

Re: Did I pull the shift assist cylinder too far?

Sure you don't just have the toe of the shift rod out of the slot in the valve/cylinder?

 

[Joe Reeves]

Re: Did I pull the shift assist cylinder too far?

Zeke has an excellent point, something I didn't consider. The shift rod has a lip that slides into a slot on the upper portion of the shift assist rod. If not in that slot, nothing works.

 

[Springcrik]

Re: Did I pull the shift assist cylinder too far?

No, it was assembled correctly. I looked at my service manual real closely, and realized that the assist piston and lower push rod are pinned together. The 1/4" of movement I was feeling was the shift valve sliding up & down in the assist piston. With the upper cover off, I could slide the whole thing, cylinder & all. to shift into FNR. and I knew that I hadn't pried on it hard anywhere near hard enough to shear a roll pin.
For some reason the shift piston was sticking in the cylinder barrel. So out came the small brass drift, and I tapped the shift piston down, which freed it all up. Worked it up and down several times, and it all works fine now.

The only thing I figure might have caused this is that I steam-cleaned the heck out the entire lower unit after I pulled it off the motor. I have been a diesel tech & service manager for 33 years, and loathe working on anything without cleaning all the grease & grime off first. The 200+degrees heat from the steam cleaner might have "gummed up" the old gearlube enough to stick the assist piston to the cylinder barrel.

So now I have rebuilt the carbs, checked the reed valves, put in a complete new water pump, decarbed and new head gaskets, new propshaft seals, and fresh gearlube. Compression is medium-fair at about 110-115 with #3 a tad low at 103 PSi. #3 cylinder has a very very slight score. I need to jerry-rig some kind of tank for test running to check timing and linkage synchronization next. Wouldn't care to tie up a boat ramp for 2 hours trying to do that.

A big thank-you Joe & Ezeke for your advice and experience.