25hp Johnson gear box(?) trouble

[JRC]

I have a 25hp Johnson and a 25 hp Evinrude. Both are early 1970s models. The Johnson was in need of gears, so I swapped the gears from the Evinrude and put them in the Johnson. They seemed to fit fine. The problem is that when the motor is in gear (either forward or reverse) the prop will spin forward and backward. Any help would be greatly appreciated. Thanks

 

[Joe Reeves]

Re: 25hp Johnson gear box(?) trouble

JRC..... You say, and I quote "The problem is that when the motor is in gear (either forward or reverse) the prop will spin forward and backward."<br /><br />I'm having a problem understanding that statement. Could you elaborate on that somewhat?

 

[JRC]

Re: 25hp Johnson gear box(?) trouble

When the motor is in gear (not running), I can spin the prop with my hand. I assume that I should only be able to spin it clockwise while in forward and counterclockwise while in reverse. But I am able to spin it both ways while in gear. I have split the lower unit and the gears seem to look alright. Is it possible that the drive shaft is broken? When I pull the rope while it is in gear nothing turns.

 

[ShafferNY]

Re: 25hp Johnson gear box(?) trouble

Does this motor have a shear pin?

 

[JRC]

Re: 25hp Johnson gear box(?) trouble

I'm not sure if the motor has a sheer pin. How can I check?

 

[alcan]

Re: 25hp Johnson gear box(?) trouble

Hi JRC<br />I would suggest that you obtain a manual. It sounds to me like you tryed to rube goldberg the thing together. If you remove the lower unit, take it to the bench and assemble properly, it will more than likely work. I know the job was not done correctly by the questions you ask.

 

[ShafferNY]

Re: 25hp Johnson gear box(?) trouble

The shear pin goes through the prop and the output shaft on the lower unit, sometimes they're behind the prop and sometimes they're on the end of the output shafts. It just depends on how yours is set-up.