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Johnson 30 Hp lower unit tear down

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I'm working on taking apart my johnson 30 hp's lower unit. This is the 1993 model. Right now I am at the stage where I need to take the prop shaft bearing housing off, and I do not have the puller that the service mannual calls for to do so. Is there some other way to remove this part without buying a $75 dollar tool?

  • Super User

I'm assuming you have the lockring and all out.

I generaly just get a stick of grade 8 all-thread and small piece of 1/2" thick flat metal, cold roll a couple of inches wide or similar. See what size you can get in there but I usually try 3/8" Bend a small hook on one end, drill two holes in the flat metal far enough apart to fit the width needed for the bearing carrier. Hook the all-thread behind the carrier and cut them off a couple of inches above the flat metal. Stick them through the holes and us nuts on the all-thread to jack the carrier out. Hopefully this is not a saltwater motor, if so, you've got a hellava job on your hands.

Oh, you will need access to a tourch to heat the ends enough to get a good, sharp bend on them. Don't try a U-turn bend, there's usually not enough room to get them in there. You might even have to grind them some to get them behind the carrier.

You might need to drill and hole in the center of the flat steel the size of the prop nut threads so it will slide on the shaft a little to get it to stay in place,

  • Author

I have an update. I will start with the minimal amount of good news and proceed from there.

I only had to spend about seven dollars on a puller, I was able to rig one out of a simple gear puller and two three inch bolts. I found a decent pair of snap ring pliers for twenty dollars, and a pair of long handled needle nose pliers for seven. That totals to 34 plus the repair manual at 42 for a grand total of $76.

Now for the bad news.

The forward gear, pinion gear, forward bearing, and pinion thrust washers are all damaged. The forward gear and pinion are destroyed, lower unit was full of chunks once I pulled the gears and could see in there. Now I know what you guys mean when you say chunks. Also, this may be the worst part, there are a couple scars that I can see on the actual gear case housing. So having said all that, my rough estimate for the gears and seals etc. is $550, however, this is if you guys think it is safe to fix it with some scars on the housing. If not, then it looks like I need to find another lower unit. Thoughts? Forgot to mention, also some minor scaring on the outside of the clutch dog, but it doesn't look really bad, probably fixable with some sandpaper. My estimate did include replacement for that.

  • Super User

Where are you talking about the scaring is at.  If it's in a non wear area then no harm done.  If it's where one of the bearings go and it's gouged it out so there in not a tight fit, then you may have a problem.  If you scared the sides getting the snap ring out, as long as it not under where the O-rings seal, shouldn't have a problem there.  If it's on a seal or wear surface, you may be able to clean it up and use some Marine-Tex or Devcon Plastic Steel Putty to fill them in and carefully sand them smooth after it dries.

With all that said, you might be able to find a good, used LU cheaper than you can fix that one.  Also, read ahead on the assembly and see if it tells you to use some special guages/jigs to set it up (shims and spacing) before you go back together with it.   If so, there is no getting around using them, it won't live, so you will have to pay a dealer or shop that has them to set it up for you. 

  • Author

The scaring is not around the bearings, its around where the pinion and forward gear sat, it was caused by some of the chunks wedging and rubbing. Ill get a pic if I can.

  • Super User

If it's not a wear surface and it didn't eat a hole all the way through, ain't gonna hurt a thing.  If it did punch through, a good TIG welder can patch it.  If you do repair it, you will want to seal it up and pressure checking it before putting it back in the water.  Just to make sure there are no small holes or cracks that made it all the way through to the outside.

  • Author

I think its safe from the damage you are describing, I didn't find any evidence of water in the oil when I drained it originally, and it was run at a pretty high rpm in reverse.  If I don't take it apart any further than it already is, then the only tool I will need will be the one to put the detent balls and spring back in.

  • Super User

It would be kinda dumb not to take the drive shaft out, replace the upper seal and check that bearing after spending bunches of money on the other parts.  If everything is good on it, the only thing you have to worry about is that retainer holding the top bearing.  You will need the jig to see if it's warped or not, if it it's, that's over $100, and they usually are.  I sure would have to spend a bunch of money and then do it half**s and have it tear up again real soon.

Now I'm not looking at a manual because I don't have any on those small motors.  I'm just going by past experiences with my stuff so your's may be different.

that's why I say, you might want to look for a good used one.  They get very expensive real quick when you start buying hard parts.

  • Author

I think I am going to go with your suggestion about finding a good used lower unit or a good used motor. I don't think I can feel confident running 15-20 miles up a river in this thing. I really appreciate you taking the time to help me with this.

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