Johnson 1990 115 Hp not shifting into reverse (astern propulsion)

[astampfel]

I can't get my outboard to shift into reverse under engine power. With th engine off, when in neutral, the prop spins freely. With the engine off, when I shift it into reverse, the prop will engage and I can't turn the prop. But when under power, the prop will not catch in reverse. Everytime since I bought the used engine (for 4 months), it would not go into reverse. Except, one time last week, I was able to get it into reverse just after I started the engine!!!! I was so excited I couldn't believe it, but when I went into forward and back to reverse, no luck. I have adjusted the thumbwheel all the way to give me maximum reverse linkage travel. I've even taken a broom handle while underway, removed the engine cover, and tried to push the shift lever on the engine into reverse, but no luck. Any ideas????

 

[astampfel]

Re: Johnson 1990 115 Hp not shifting into reverse (astern propulsion)

Update: I removed my shift cable, and moved the lever by hand. It goes into forward and neutral very nicely, but when I try to move it to reverse, it doesn't want to go. So, I watched the linkage (shiftrod going to the lower unit), and it seems like right at the top of the rod, there is a designed bend, and that bend is getting stuck on the engine housing! Coud the shift rod be adjusted too far down which causes this interference? I'm thinking the only thing I can do know is remove the lower unit, adjust the shift rod heigth a few turns, and see if that works. I'm open to suggestions, thanks!
Andrew

 

[boobie]

Re: Johnson 1990 115 Hp not shifting into reverse (astern propulsion)

I think you're right, it sounds like a shift rod adjustment unless something is really worn in the g/c. Get a service manual to check the spec first before doing any adjustments.

 

[twostroke87]

Re: Johnson 1990 115 Hp not shifting into reverse (astern propulsion)

if you take the lower unit off you will find the shift rod goes through a bushing and plate down into the lower. It is very common for those to corrode up with salt at that plate. This is most likely your problem. Drop your lower unit, unbolt the plate and unscrew the shift rod. Slide the plate off and throw it in the trash, this plate is not that expensive and will solve your problem. Count the turns as you unscrew the shift shaft.

When you install the new plate, and slide the shift shaft down to screw it in, screw it in the same amount of turns you counted coming out. Then check with your manual and measure the height to make sure its right.

I am 90% sure this is your problem. Good luck and take your time.

 

[boobie]

Re: Johnson 1990 115 Hp not shifting into reverse (astern propulsion)

If the shift rod bushing or plate is corroeded it wouldn't go into forward or neutral easely either. Stick with the shift rod adjustment.

 

[Auxlarry]

Re: Johnson 1990 115 Hp not shifting into reverse (astern propulsion)

I agree with boobie and the others in that the shift linkage is out of adjustment. Could be that when someone installed a new water pump they had no idea that this rod has a very specific length for proper operation and screwed it all the way down to the end of the threads. Pull the LU, get a manual and adjust the length of the rod to spec. These adjustments are very specific and only give you about 1/32" to 1/16" to play with for proper shift operation.

 

[Auxlarry]

Re: Johnson 1990 115 Hp not shifting into reverse (astern propulsion)

My book calls for you length to be 21 27/32" +/- 1/32". This is from the top edge of the LU casing to the center of the hole in the shift rod.

 

[boobie]

Re: Johnson 1990 115 Hp not shifting into reverse (astern propulsion)

Aux's measurements are right on. If or when you pull g/c off, check the measurements before doing anything.