Trouble seating lower leg after impeller change - 1982 Chrysler 75 hp

rkinross

Cadet
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Jan 23, 2017
Messages
29
This is the first time since I purchased the boat that I changed the impeller. Everything went fine with the removal of the lower unit and impeller. I cleaned up the impeller housing and all of the bolts. The problem I am having is inserting the lower leg back into the motor and lining up the splines on the drive shaft and the splines on the crank shaft. The crank shaft seal also keeps falling off whenever the lower unit gets up there and I try to giggle it around to get it to seat. I went out and purchased a ratcheting tie down strap to try to help lift the unit into place. https://www.youtube.com/watch?v=srGVSl4_n8Q I also put the engine in forward gear before I started the process but the drive shaft does not turn when I turn the propeller. (it must have been placed into neutral somehow) I can still turn the fly wheel to get the splines to line up. Are there any other techniques to try to get the lower unit to re-seat. There are 3 things I am trying to line up: the crank shaft and drive shaft, the water tube, and the shifting rod thru the hole so that I can reconnect it. This thing is heavy and when it doesn't seat the up and down movement in trying to seat it makes the crank shaft seal fall off so then I have to start over. I have been at this for hours with many attempts and still no go. Thanks in advance for any help.
 

Nordin

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Jun 12, 2010
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2,428
I suppose when you says crank shaft seal is falling you mean the rubber boot that should seal from water to enter the crank spline.
If do not have any assistant that can help you then I would suggest you to use a jack (floor jack with wheels).
I use one when I assemble lager LUs alone.
Put the skeg at the plate then you can lift the LU with the jack and you are able to line up and check the pick up tube and shift rod with you other hand.
Try to line up the splines between the drive shaft and crank by turning the flywheel.
You can not turn the drive shaft by hand cause the impeller is holding it.
 

jerryjerry05

Supreme Mariner
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May 7, 2008
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17,923
Install the prop or use a pair of vice grips.
Push the shift rod down and then lift the drive
up into the cavity.
As your lifting turn the prop lift up on the closest
ear or grips(props easiest)
and hopefully it slides up into the right spot.

Since the impeller is new, the shafts turn real hard, using the prop
and being in gear helps.

Rubbing salt into the wound:
Guy calls and says he has the same problem :(
He says I can have a running 125 IF I can get this F%^(& drive on.

He says I'm going to get a drink and will be right back out.
I followed my instructions and before he opened his refrigerator the
drive was on and I was tightening the bolts.

He almost passes out.

The motor was left there, just charged him 30$
 

rkinross

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Joined
Jan 23, 2017
Messages
29
Nordin Yes, the rubber boot is what I am calling the crank shaft seal. Would it be a good idea to put a dab of rtv on the base of the rubber boot to hold it in place or will it cause other problems? Is the boot supposed to spin along with the crank shaft when the motor is in operation?
 

rkinross

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Jan 23, 2017
Messages
29
jerryjerry05 The prop is already attached to the lower unit. Would pushing the shifting rod down put the gears in forward or reverse? Should I adjust the throttle at the drivers seat controls to match the gear it is in? I am trying to avoid shifting problems after the install is complete.
 

Nordin

Commander
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Jun 12, 2010
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2,428
Yes maybe the boot is turning with the drive shaft i believe It is squeezed between the retainer cup and the crank shaft.
It seams that you do not have the retainer cup cause it would hold the boot in place.
The boot is not necessary, you can coat the spline with a thin amount of marine grease instead.
No grease at top of drive shaft, it can create an hydraulic issue.
The boots purpose it to seal the spline from water and to avoid rust in the crank shaft spline..
 

jerryjerry05

Supreme Mariner
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May 7, 2008
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17,923
It doesn't matter what gear it goes into as you'll change
it when you hook up the linkage after the install.
I think pushing down puts it in Forward?
Then pull up on the blade with your right hand and the shafts
should turn allowing the splines to mesh.(maybe??? :) )

To make this clear, Nordin said no grease "at the top" he means
no grease on the end of the shaft.
But use plenty on the sides and under the boot.
If you have the time, get all the grease off the boot and the ring.
Then glue them together, let dry.(didn't see Nordin suggested RTV
 

rkinross

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Jan 23, 2017
Messages
29
Nordin Yes I do have the retainer cup. The retainer cup has groove that faces up when I put it back on the drive shaft and the rubber boot goes on with the beveled end up. The boot fits right into the groove in the retainer cup. This is where I was thinking a dab of RTV would go. I think jerryjerry05 was agreeing that using a dab of RTV on the retainer cup was a good idea to hold the boot in place.
 

rkinross

Cadet
Joined
Jan 23, 2017
Messages
29
jerryjerry05 and Nordin - I have successfully reattached the lower leg back onto the motor. It was not easy. I had 2 other people helping line it up and used a floor jack to assist with raising it into the motor. The advice on pressing the shifting rod down to put it into gear was very helpful. Turning the prop to align the splines is much easier than turning the flywheel. It was also helpful to lower the motor all the way down after the drive shaft was installed to assist in lining up the crank shaft with the drive shaft. Thank you both very much for assisting me with your advice on how to complete this job. Regards, Bob
 

jerryjerry05

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May 7, 2008
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Just send the check :)
Glad it helped.
I get on here in the mornings as my way of waking up.
This and my daily cup of coffee and I'm ready to go(after an hour).
 
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