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Johnson 1998 2cyl 2strk 50hp Lower Unit - R and FWD not working

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bigtime_mcalpine

Regular Contributor
Hi,
I'm hoping I won't be kicking myself for having picked up this motor but anyway, it's mine now. I purchased it knowing it had a defective LU. I don't have it in hand yet but it's obviously going to need some LU work.

I've done a bit of research which suggests that overhauling it gets expensive fast. I'm hoping that's not the case. A quick scan of ebay gives me some pretty poor options for getting a hold of a used working one and my local dealer tells me this is one of the rarer lower units to find on the used market.

Have any of you replaced the gears/pinion on any of these bad boys? I see that parts are available and I'm assuming that I'm likely in for pinion and fwd gear, maybe a reverse gear, an o-ring, maybe some needle bearings but hopefully not. Wondering what the typical gotcha's are.

Any feedback would be appreciated.
 
I say it all the time.-----These lower units are flimsy.-----Huge demand for them.---That is why hard to find,------Likely the teeth ripped off the pinion and forward gear.----Metal bits all through the bearings.-----Requires special shimming tool.----Or an experienced touch to fit gears.----Sorry to be blunt here.---Not the same as installing sparkplugs !
 
racerone said:
I say it all the time.-----These lower units are flimsy.-----Huge demand for them.---That is why hard to find,------Likely the teeth ripped off the pinion and forward gear.----Metal bits all through the bearings.-----Requires special shimming tool.----Or an experienced touch to fit gears.----Sorry to be blunt here.---Not the same as installing sparkplugs !
Click to expand...
You kidding? Blunt is what I need. I see, didn’t think through the implications of the “metal bits everywhere” now I get it. So do-able, probably more extensive than assumed AND at least one gotcha (the shimming bit). Thanks Racerone. Will update on progress or lack thereof.
 
racerone said:
I say it all the time.-----These lower units are flimsy.-----Huge demand for them.---That is why hard to find,------Likely the teeth ripped off the pinion and forward gear.----Metal bits all through the bearings.-----Requires special shimming tool.----Or an experienced touch to fit gears.----Sorry to be blunt here.---Not the same as installing sparkplugs !
Click to expand...

Hey racer - quick question for you: for the shimming, I could just bring in the drive shaft, pinion gear, and washers into my local shop, right? Or would I need to supply him with the entire lower unit housing too?
 
Update: Racerone guesses almost spot on. I took the LU apart at lunch:

- Rear gear: fine
- Pinion: damaged
- Forward: further damaged
- Upper thrust bearing: obliterated (part 34 in diagram below)
- Pinion bearing: all but destroyed (part 2 in diagram below)
- Shims: 1 was mashed up, second was fine, 3rd seems to be permanently imprinted onto upper bearing housing (may just leave there, not sure)
- thrust washer: seems to have picked up some metal on outer edge and the metal is now a permanent part of the washer. I don't think this is an issue but will confirm.
- Forward needle bearing assy: fine
- Reverse flat needle bearing: fine
 
Bearing housing in 3rd picture is SCRAP.-----Unless you are well versed in machining.----All bearings should be replaced.
 
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