Used LU driveshaft does not turn, prop shaft does - 1978 Johnson 115 LU

grossgary

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My LU failed so I got a "working condition" used 1978 Johnson 115 lower unit.
The driveshaft doesn't turn by hand no matter what position I put the shift rod in. I put a large monkey wrench on it - and no movement.

What next?
What position of the shift rod should allow it to turn?

Looks like most people will say to remove the water pump impeller - will that really prevent the shaft returning with the leverage of a monkey wrench?

Assuming that doesn't work- then what?
 

racerone

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Remove the bearing housing under the water pump for inspection.----Just 4 small bolts and pry it up.---That will tell a big part of the story.
 

Faztbullet

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Sounds locked up to me....wonder when the last time it was in working condition?
 

grossgary

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is that bearing housing prone to difficulties removing like the one for the prop shaft? i can't get the bearing housing out of the original LU, which is why I bought this one.

It was shipped without oil. I talked to him tonight and he said it was off an engine that blew a cylinder and he turned over by hand and suspects it's just tight from sitting. i'll pull the bearing housing and see what it looks like.
 

Faztbullet

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suspects it's just tight from sitting
The only reason they get tight for setting is unit had water in it and bearings locked up, I have stored units in shed that been setting for years and they turn easy by hand...
 

emdsapmgr

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It's not a big deal to pull the carrier/propshaft out either. You'll get a good look.
 

grossgary

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Remove the bearing housing under the water pump for inspection.----Just 4 small bolts and pry it up.---That will tell a big part of the story.

I pried that housing up about 1/2" and the driveshaft now rotates with the housing. So I presume the driveshaft is stuck to that housing?

I'm unsure if the entire housing/driveshaft combo "lifted" that 1/2" or if the housing did actually slide up the driveshaft 1/2", I'll check.

Any tips on removing that housing more than the first 1/2" Are there seals/bearings under there that will be damaged by my torch?
 

grossgary

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The bearing housing comes up about 1/4" maybe - then pulls the driveshaft with it a little bit more, then stops, won't come any further. So the bearing housing isn't necessarily stuck to the driveshaft...sort of...exactly, I'm unsure.

the driveshaft does rotate, though seemingly "with" the bearing housing at times...the bearing housing does move vertically without the driveshaft moving at first so that seems like a decent sign. in the end it stops, can't get it past 1/2" maybe 3/4".

just keep working it back and forth? it seems like eventually that thin metal is gonna fatigue and fail, it's getting warn/dented.
 
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grossgary

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The driveshaft and prop turn smoothly now - though I never got that bearing housing out.

Can I simply reseat it and reassemble?

Is that bearing housing flange sealed against the LU housing/shaft bore? I don't see any gasket or sealant there but seems like there would be gear oil down there.
 

racerone

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No, no , you are trying to find the easy way out and that does not work.-----Pry that bearing housing up and out.---It is abundantly clear to me that there are damaged bearings on the upper part of the driveshaft !!!
 

grossgary

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how does that bearing housing come out? i'm already starting to damage the housing flange from pryin/banging on it.

I would rather get it off of course, yet there is a slight difference between easy way out and something that can't/won't be done or does more damage.

"work that way" - dependent on perspective:
if it try it - there's a percentage chance of it working.
if it I can't get it apart or break something in the process - there's a zero chance of it working.
 

grossgary

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thanks. i'm not familiar with boats and how much pulling/prying is normal/not normal. i ended up breaking a chunk of metal off the LU case that the housing seats against. it's a sizable chunk and repairable via welding.

once the bearing housing came out, there are chunks of metal under the bearing housing that looked almost like gear teeth but the "bearing" - if i'm looking at this correctly - looked intact with tiny needle bearings in place. not sure what all those bits and pieces are. they look too large to be bearing bits - and the bearing looks intact.

anyone know what I'm seeing?

is it possible to flush the system through the drain hole top to bottom?
or is this thing just hosed and needs completely disassembled and cleaned out?

i guess i can see if that lower prop shaft carrier bearing comes out - but the one i'm trying to replace wouldn't move - pulling and torch = no movement.
 

grossgary

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i disassembled the original LU (and the bearing housing pried right out without issue) and it has another set of bearings under the bearing housing (where the needle bearings are housed). this set of bearings is completely missing from the "new working LU", no housing or any remnants at all of a functional "part" - that must be the source of the ground up metal bits and racerone was on it from post #1:

Remove the bearing housing.....That will tell a big part of the story.

guy said he'd give me my money back so we'll see how that shakes out...

thanks for the help.
 

jakedaawg

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Post the model number. I have several lowers. one of mine may work. Is this long shaft?
 

grossgary

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Post the model number. I have several lowers. one of mine may work. Is this long shaft?
Model number: 115ML78C
Short shaft

1978 Johnson 115 hp

If you got a lower unit, let me know.

It can be tough to " coach " some folks.
copy, i get it, sorry to be frustrating or wasting your time, i get that you're helping and that's fantastic for us new folks. internet does make it challenging to converse. i've never disssembled a LU so I'm flying blind minus the factory service manual which isn't always clear to me.
 
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