Need help with 1977 Johnson 25HP.

[reaper2332]

I recently purchased a 1977 Johnson 25HP motor. I can spin the prop by hand when its in forward, neutral, and reverse. I thought it was either a spun hub or a broken shear pin. I replaced the prop and the shear pin isnt broken. If it helps when I spin the flywheel in neutral the prop spins as well. Can somebody please give me some ideas on what this issue could be? Also I am a complete newb when it comes to boat motors, but I do have some experience with regular car motors.

Thanks,
Jason

 

[Joe Reeves]

Re: Need help with 1977 Johnson 25HP.

Did this engine function okay prior to this problem... or is this engine new to you and this problem has existed from day one?

From what you've described, it sounds like either the shift linkage isn't hooked up to the lower unit properly, OR the driveshaft has sheared at some point.

 

[steelespike]

Re: Need help with 1977 Johnson 25HP.

Usually if the motor is off you may have to rotate the prop to get it in gear.In gear the prop will rotate about 1/3 of a turn.
Its normal for the prop to move some even in neutral as the flywheel turns.
The forward and revers gears are free on the prop shaft always driven be the driveshaft The clutch dog is splined to the prop shaft
and slides to select forward or reverse. The shift rod has a connector in the leg behind a little window.it may
be assembled wrong. Check at the shift lever to see if the upper rod moves as you shift.
If the connector seems ok then any number of things could be wrong in the gear case.

 

[reaper2332]

Re: Need help with 1977 Johnson 25HP.

Did this engine function okay prior to this problem... or is this engine new to you and this problem has existed from day one?

From what you've described, it sounds like either the shift linkage isn't hooked up to the lower unit properly, OR the driveshaft has sheared at some point.

Long story short, the motor is new to me. I havent even tried to start it yet. Anywho I removed the little plate on the starboard side of the engine to check the shift linkage, it looks as if it is hooked up correctly.

When i put the motor in gear, when i first start to spin the prop the flywheel spins as well but shortly after the prop spins but the flywheel does not.

Not sure if I am giving you the information you need.

 

[reaper2332]

Re: Need help with 1977 Johnson 25HP.

Usually if the motor is off you may have to rotate the prop to get it in gear.In gear the prop will rotate about 1/3 of a turn.
Its normal for the prop to move some even in neutral as the flywheel turns.
The forward and revers gears are free on the prop shaft always driven be the driveshaft The clutch dog is splined to the prop shaft
and slides to select forward or reverse. The shift rod has a connector in the leg behind a little window.it may
be assembled wrong. Check at the shift lever to see if the upper rod moves as you shift.
If the connector seems ok then any number of things could be wrong in the gear case.

- When I have the shifter in forward i can spin the prop all day. When i first start to spin the prop the flywheel spins aswell but shortly after the prop spins and the flywheel doesnt.

-When i removed the little window and move the shifter the linkage moves up and down (Both the top and the bottom).


Also when I purchased the both and motor, it looked as if someone didnt tie up the motor before transport and hit the prop on the ground going over a bump.One fin was bent about a 1/4" up at a 90 degree angle. I checked the bottom of the foot and there was only a little scrape.

 

[boobie]

Re: Need help with 1977 Johnson 25HP.

I'll have to go along with Joe Reeves, spun drive shaft.

 

[reaper2332]

Re: Need help with 1977 Johnson 25HP.

Is that something I could fix myself?

 

[Joe Reeves]

Re: Need help with 1977 Johnson 25HP.

Is that something I could fix myself?

Yes, you should be able to handle that job if it is indeed a sheared driveshaft. The starting point at any rate is to drop the lower unit to check that shaft.