1975 Johnson 25hp (25R75B) Jumping out of gear.

[baseball_guy_99]

Bought this motor, took it out to the lake...after giving it some throttle, it kicks out of gea (like i hit a log and the motor revved up). I could put pressure on the shift lever and it would still kick out of gear. Reverse works fine. So my first thought is clutch dog and forward gear. Well after seeing the price for those I hunted down a used LU.

Long story short, the prop shaft was too short so I gutted that lower unit and put everything into my LU. Took it back out today. Took off, got up on plane, bout 3/4 throttle and it kicked out of gear. The only things I didn't swap we're the shifting fork, the shift rod, and the pinion gear.

I also noticed that shifting out of gear into neutral, it doesn't always go into neutral. I have to jiggle it a little to get it to go into neutral.

Any thoughts?

Thanks in advance!

 

[Beek14]

Re: 1975 Johnson 25hp (25R75B) Jumping out of gear.

Possibly unlikely, however it could possibly be slipping shift linkage. Did you inspect the forward gear and clutch dog that you put into the lower unit to see if there was any rounding of the ears? It doesn't take much to cause it to want to slip.

 

[baseball_guy_99]

Re: 1975 Johnson 25hp (25R75B) Jumping out of gear.

They looked better than what's was in there.

I was told by someone else to adjust the shift linkage as well. I do that by loosening the two bolts on the shift lever and then move it slightly towards neutral correct?

 

[AlTn]

Re: 1975 Johnson 25hp (25R75B) Jumping out of gear.

yes, to bias it towards forward move the shift handle towards reverse...how much clearance do you have in the shift cradle to shift dog fit?...it should be almost none...any clearance there will make a "jumper" more likely to jump

 

[baseball_guy_99]

Re: 1975 Johnson 25hp (25R75B) Jumping out of gear.

Are you. Talking about the little U shaped cradle that the clutch dog rests in?

If so the clutch dog fits snug.

 

[steelespike]

Re: 1975 Johnson 25hp (25R75B) Jumping out of gear.

I believe these motors have detent balls in the prop shaft that help maintain the clutch dog position.
These may be missing.

 

[baseball_guy_99]

Re: 1975 Johnson 25hp (25R75B) Jumping out of gear.

Steele thanks for the suggestion, but those are both there along with the spring.

I think I'm just going to buck up and buy a new clutch dog and forward gear.

 

[baseball_guy_99]

Re: 1975 Johnson 25hp (25R75B) Jumping out of gear.

Update...I did the "adjustment" (at least I think I did). Took it out to the lake this morning and sure enough...gave it gas and it jumped out of gear. So I reached back and grabbed the shift lever to put some pressure on it.

It stayed it gear all the way across the lake, but as soon as I took my hand off the shift lever, it came out of gear.

So do you think it needs more adjustment, or do I need a new clutch dog. I think I'm leaning towards the latter option.

 

[AlTn]

Re: 1975 Johnson 25hp (25R75B) Jumping out of gear.

forum member kfa just got a heckuva deal on a dog and fwd gear from Bobby Chapman, BLC Marine, Dickinson, Tx. email BLCinspec@aol.com, 713-705-0664, 281-337-1805..I had the dog and gear refaced at a machine shop < through a dealer > for $95, but, yeah, I'd saw you are to the replace/repair option now..you can check marineengine.com for the dealer price if you want a sticker shock

 

[baseball_guy_99]

Re: 1975 Johnson 25hp (25R75B) Jumping out of gear.

I found a new dog and forward gear on eBay for $170. I jumped on it.

It's expected to be here this weekend.

 

[AlTn]

Re: 1975 Johnson 25hp (25R75B) Jumping out of gear.

that is a good price...gonna do the seals now or just replace the spaghetti seal and reseal the 2 halves?

 

[baseball_guy_99]

Re: 1975 Johnson 25hp (25R75B) Jumping out of gear.

I just replaced the spaghetti seal and the prop shaft one. I'll check for water intrusion and go from there.

How hard is it to get the forward bearing off the old gear because I didn't order a new one of those?

I'm also having trouble finding a part in the diagram. If anyone wants to pm me their number or emAl addy I can send a picture of what I'm after.

 

[AlTn]

Re: 1975 Johnson 25hp (25R75B) Jumping out of gear.

bushing slips out..can you post a pic or describe the part?

 

[baseball_guy_99]

Re: 1975 Johnson 25hp (25R75B) Jumping out of gear.

I'm at work so the only pic I have is on my phone.

I'll do my best to describe it.

It's a small white piece that goes on the bottom part of the shift lever. It slides onto the small shaft that moves up and down in the (I'll call it an inverted) "E". That shows you what gear you are in. I lost it the other day when I was working on the motor.

 

[AlTn]

Re: 1975 Johnson 25hp (25R75B) Jumping out of gear.

yeah, that nylon/plastic roller?..I don't see it in the diagrams either...got any marine salvage yards nearby?...dealerships?...repair places..most keep some kind of boneyard for spares...at least the old school ones do

 

[baseball_guy_99]

Re: 1975 Johnson 25hp (25R75B) Jumping out of gear.

Ya that's exactly the piece I'm looking for. I lost it the other day while working on my motor. I wonder why it's not listed. Is it absolutely necessary to have?

I don't have any near by. Guess I'll just keep a look out on eBay.

 

[baseball_guy_99]

Re: 1975 Johnson 25hp (25R75B) Jumping out of gear.

Anyone know if that piece is a necessity?

 

[Beek14]

Re: 1975 Johnson 25hp (25R75B) Jumping out of gear.

If I'm on the same page of what you're talking about, no it is not a necessity per say. It just helps your outboard shift smoother. Without it, it will be basically metal to metal which can cause hard shifts which can be hard on the gears/clutch dog. Also, I would imagine over time it would wear down that part of the shift lever and throttle advance lever (the e lever).

 

[baseball_guy_99]

Re: 1975 Johnson 25hp (25R75B) Jumping out of gear.

Hmm ok thanks Beek. I'll just keep my eye out for one or hopefully i can find the one I lost!