1993 Johnson 48hp lower unit rebuild

[roscottjr]

Rebuilt my lower unit due to a gear going bad. Lost about 4 teeth on forward gear and also on the pinion gear. Reverse gear was fine. I found that the forward gear bearing didnt look so great on one side. My new part consist of: forward gear, reverse gear, pinion gear, clutch dog, both clutch dog springs, forward and revers gear bearings and thrust washers, water pump set, lower unit seal set. The remaining bearing in the case looked and checked out fine as per manufacturer specs. I reassembled the gearcase useing the recommended oils and greases where noted in the manual. Filled unit with recommended hi-vis gearcase oil. Started engine (on muffs) and ran for about 15 minutes changeing between forward, neutral, and reverse gears to make sure everything was operating correctly. I also used a mechanics stethoscope to listen for sounds in the gearcase but heard none. After running I shut it down and removed the lower drain screw and upper screw to be sure it was full of fluid and noticed metal particles on the magnetic screw. Nothing big but more like tiny particles or tiny shaveings. I cleaned all the metal off the screw and my plan was to do this several more times and see if it is still doing this and if so then take the unit back apart and se whats going on. Does anyone have any suggestions or is this normal and I am just jumping the gun here.

Robert

 

[jonesg]

Re: 1993 Johnson 48hp lower unit rebuild

It might just be seating, small particles are normal, they don't have a clutch, we just bang em into gear. Larger shavings and chips are bad.

 

[roscottjr]

Re: 1993 Johnson 48hp lower unit rebuild

Ok, just as a precaution I decided to take the gearcase back apart to make sure the metal wasnt anything major. As best I can tell there is no damage on bearings, thrust washers, or gears. However, There is a shiny ring around the forward gear where the pinion nut is. Looks like the pinion nut is rubbing on the forward gear. What would cause this and how can I fix it? I have checked the manual again and the only shimming it shows for the pinion looks like its just to keep the pinion from moveing up and down. I have checked the measurements and everything is within specs. However, the driveshaft still slightly moves up and down if you push and pull on it. Does anyone have any idea what is going on here or is this normal? I usually check to see how everything is before disassembly but I never even thought to check if the driveshaft slightly moves up and down. If I had to bet on it, I would say this pinion nut riding on the forward gear is causing my metal particles but I dont see how to fix the problem.

Robert

 

[roscottjr]

Re: 1993 Johnson 48hp lower unit rebuild

Well, I got the case apart and found out it is not the pinion nut. When I rebuilt the unit I replaced all 3 gears, clutch dog, thrust bearing and thrust washers. The remaining bearing looked good and still do. The new parts show no signs of wear or scratching and neither does the case or any of the bearings in it. Is it possible maybe these metal particles were missed when I cleaned the case before? I dont see anything that is coming apart but the metal particles concern me. Any ideas?

Robert

 

[roscottjr]

Re: 1993 Johnson 48hp lower unit rebuild

I havent had time to go to the lake and see how the lower unit runs but since I couldnt find anything that looked like it was going bad and noone else had responded, I am assumeing it is just normal seating of the new parts and shouldnt be anything to worry about.

Robert