1991 Johnson 70-HP Shift Rod

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
Pescatore
Posts: 17
Joined: Sun Jan 17, 2016 9:10 am

1991 Johnson 70-HP Shift Rod

Postby Pescatore » Mon Mar 27, 2017 8:43 pm

[On a] 1991 70-HP Johnson I removed the lower unit along with the shift rod. The shift rod pulled out from the lower unit. I went to put back the shift rod by screwing it into the lower unit. The shift rod did not stop turning, so I reinstalled the lower unit and connected the shift rod to the top of the engine.I started the engine and shifted it in and out of gear a few times. I am worried that the shift rod will pull of of the lower unit. Any ideas on how the shift rod is connected to the lower unit?

conch
Posts: 172
Joined: Sat Oct 17, 2015 8:43 am
Location: Florida Keys,Hawaii,Mississippi

Re: 1991 Johnson 70-HP Shift Rod

Postby conch » Wed Mar 29, 2017 8:41 am

Check your service manual for the shift rod height measurement for your engine. With the shift rod offset to the front ,the height for my 1998 70hp Johnson 20in shaft motor in neutral is 21 15/16in. If the shift rod is completely removed,start with an initial 9 turns in.
The height is measured from the shift rod hole to the surface of the gearcase. There is tool for this P/N 389997
Chuck

johnyrude200
Posts: 5
Joined: Wed Sep 28, 2016 10:27 am

Re: 1991 Johnson 70-HP Shift Rod

Postby johnyrude200 » Sun Aug 27, 2017 10:24 pm

Why did you remove the shift rod? Is the O-ring seal failing?

Generally that is not something you should do. With these motors, if you remove and replace, screw them all the way back in. You will need to put the gearcase back on and do a little bit of trial and error with adjusting the height to insure the clutch dog is getting the proper sweep for full gear shift.

You can screw the 5-6 gearcase screws back onto the exhaust housing the first few threads (not fully bolted on), reattach the shift rod to the powerhead shift lever, and experiment with the correct height. This allows you to rotate the shift rod while connected to the powerhead without pulling it off each time you realize the sweep of the clutch is wrong. In between tries you'll obviously have to push the shift lever detent in/out to release the shift rod between calibrations. Did you remove the retaining pin off the shift lever in the first place when removing the gearcase?

As principle, it should be an even sweep at the shift lever between F-N-R. At the CONTROLS, cheat them toward favoring forward gear shift to prolong transmission longevity.

ALWAYS IDLE DOWN LOW AND SHIFT FAST!!!