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Took Lower Unit off for Impeller Replacement, Can't Get it Back in Properly

S

Swarlos

Regular Contributor
Hi folks, I have a 1968 Johnson 3hp, JHL-23M, I replaced the impeller today, but for the life of me I can't get the lower unit back on so that it fits snugly. I fought with it for about 50 minutes, but the best I can get is flush on the front with a 5/16" gap toward the back (prop end). I'm getting the water tube into its slot, and there's only one way for the impeller assembly to go in with the offset screws. I just can't seem to get the drive shaft exactly how it needs to be. Any thoughts?
 
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That's a '68 Johnson 3 hp? Okay....non weedless. Sure your going for the right hole? Is this your first time?
 
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I removed the lower unit to check the impeller early last year and decided it could wait until now. So it's not my first time, but my second time.
 
There's no gear shift on this thing so there's only one hole to aim for.

Ok, I guess there isn't anything I can do but to keep trying. Thanks folks.
 
If water tube is properly in its place, it helps if you turn propeller just little bit at the same time while trying to put the unit place. My 3hp, propeller turns counterclockwise. Are you sure that waterpump housing is properly assembled and enough tight.
 
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You have to make sure you keep the lower unit and bottom end lined up.----Should take no more than a few minutes to install the lower unit.----Rotate flywheel to line up the splines.
 
racerone said:
You have to make sure you keep the lower unit and bottom end lined up.----Should take no more than a few minutes to install the lower unit.----Rotate flywheel to line up the splines.
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It looks too " nearly there" for the splines not to be lined up and partly engaged ...... ?? Do you think ?

I wonder if they have been over greased and there is a blob of grease on the end of the shaft preventing it going in any further ???
 
The splines on the drive shaft are clean, it definitely feels like it's going into the slot at least partially, but it just doesn't quite get there.
 
Swarlos said:
The splines on the drive shaft are clean, it definitely feels like it's going into the slot at least partially, but it just doesn't quite get there.
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racerone said:
It is not lined up with the hole in the crankshaft.----Missed it by 1-1/2 " or so !!!!
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It'll be easy to tell if its partly engaging with the crankshaft or missing it altogether by turning the flywheel. If the prop turns as well they are at least partially engaged. If its missed by a mile then the prop wont turn.
 
Thanks everyone for the advice. I went back down today and got it in there. I was visualizing it wrong thinking the drive shaft should be centered in the tube. It fits perfectly now. How hard should I torque the bolts?
 
Good job, by your photos I could see you were way off....Racer noticed that by calculating the angle of difference between the 2 parts. Torque? I never measured but I never had one come loose....they seem to stay tight, even with a dab of anti seize.
 
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