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1982 15 HP Johnson - Long to Short Shaft Conversion issues

CMOS

Regular Contributor
Howdy All,

I found this motor on CL a few months ago and was able to get it for $200. Good spark on both coils and 120/120 compression. Looks like it's been sitting in someone's garage for quite a while. I've been working on "the list" of things to do when buying an non-running motor and all is going fairly well.

When it came time to replace the T-stat I found it easier to pull the entire head than to just pull the head's water jacket cover. I was almost considering the presumption that maybe the T-stat was good and I wouldn't have to do it at all. Darn good thing I pulled the head because the entire length of the water passage under the T-stat cover was caked with - something resembling an old insect nest. And I mean CAKED. Head is now freshly painted and re-installed with new T-stat and all new seals.

Now to the issue at hand: the lower unit. I removed the 5" long shaft spacer, painted the entire lower, cut down the length of the water tube, rebuilt the water pump, replaced DS bearings, replaced the lower shift rod with a "standard" length, and installed a "standard" length drive shaft (# 0329510) that I bought on Ebay. I communicated with LeeRoy on LeeRoy's Ramblings and he did confirm that the drive shaft I have is correct.

The problem is that I cannot get the lower to fully make contact with the upper housing. There is about a 3/4" gap. I completely removed the shift coupler to eliminate any possible interference, but to no avail. Still have the 3/4" gap.

More info: if I insert the lower into the upper as far as it will go, and turn the flywheel, the prop shaft turns, therefore the upper splines of the drive shaft are engaged into the power head.

When I manually rotate the drive shaft on the lower (CW direction!) the prop shaft turns so I *THINK* the drive shaft is installed in the lower properly.

So, considering the above 2 sentences, what are your thoughts?

I guess it is possible that the drive shaft I have is NOT what I was told by the seller on Ebay. Something I have to consider.

Thoughts?

CMOS
 
Racer, I'll have to pull the short shaft out of the lower to take pics.

I have a potential theory that hit me today: The length of the upper splines on the old long shaft looks to be about 1/2-5/8" in length. By comparison, the length of the splines on the short shaft is about 1-1/4", the difference between the two just happens to be the approximate distance of the gap that I cannot close between the lower and the upper housing . . .

CMOS
 
do you have the drive shaft in right 4 splines about 3/4" from the oring seal go into the motor the other end has about 10 or 11 splines goes into pinion gear make sure those are all lined up or check to see if your original drive shaft snapped in the motor
 
do you have the drive shaft in right 4 splines about 3/4" from the oring seal go into the motor the other end has about 10 or 11 splines goes into pinion gear make sure those are all lined up or check to see if your original drive shaft snapped in the motor

Yes, 11 spline end into the lower. Power Head recess is clear.

Also, I will try to attach a pic - there is no slot on the short shaft for the small DS O-ring.

CMOSDSCN6176.jpg
 
?????-----The newer motors did not use the o-ring groove !!----They used a second seal in the lower part of the seal housing.
 
Try this you may not have it in the crankshaft as far as you think you do. make sure the water pipe is lined up and once you connect the shifter put it in gear and turn the flywheel as you push it up you may just have a minor misalignment
 
FS,

I will try AGAIN, but I don't think it's an alignment issue. I've tried this about a dozen times and I still get that same gap of about 3/4". Frustrating. Unless I find a solution I'll be pulling the DS from the lower this weekend.

CMOS
 
Post pictures of the lower parts of the driveshaft. And is the length from water pump flat to the top exactly 5" shorter ?
 
Racerone, I will take pics of the DS this weekend when I have time to disassemble. Not sure of what you are asking in the second question. I removed the 5" spacer, cut the copper water tube by exactly 5", installed the "new" Ebay DS, then replaced the lower shift rod with a new "short" version.

CMOS
 
Bingo!

I started to think that I needed to look in areas that I have not considered as of yet. I tried to insert the lower into the upper again, paying attention to the sound of the DS hitting the Power Head. The sound of the obstruction did not sound like it came from that upper end. It sounded like it was right down at the lower unit itself.

A quick inspection up inside the upper housing revealed that the copper water tube was slightly canted to one side - not centered. The copper tube was hitting the impeller housing!

Once straightened, the lower and upper went together just fine.

Learn somethin' new every day . . .

CMOS:eek:
 
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