Lower unit won't go all the way in

[94crestliner]

I've got a 1993 Evinrude 20hp 2 stroke outboard that I just replaced the water pump kit on. I changed it because there was no water coming out of tell tale when I had it running on the muffs. All last year water flowed freely from it while I was using the muffs. I'd done all the checks suggested from other threads on this forum to make sure there were no obstruction from the water tube in the lower unit through to the end of the tell tale tubing before replacing the pump.

I changed the kit with it in neutral (it was an OEM kit) using the manufacturer's instructions that were included with the kit. I put the lower unit back on, then ran it on the muffs and in a plastic tub - still no water from the tell tale. I took the lower unit off again, re-checked everything (gaskets, key in the driveshaft, impeller put in properly, bolts, etc). I went to put the lower unit back on to test it again but it won't quite got all the way in - it's slightly more than 1/4" out. When I put it back together the first time, it went in fully with no gap at all, though I had to turn the flywheel a bit to seat it properly. I've tried several times now while moving the flywheel and still always end up just that 1/4" out.

​I've read that the splines at the top of the drive shaft may not be quite in line with the shifter gearing? The water tube isn't a problem - I removed it entirely to eliminate it as a potential cause of the gap. I can easily re-install it once the gap is no longer an issue.

Would love some help with this

 

[gm280]

:welcome: aboard 94crestliner to iboats. Great to have you join us...

Did you put and grease on the upper drive shaft splines? If so, you could have caused a hydraulic lock trying to force the drive shaft up into the crankshaft splined recess. You could clean it off and apply just enough grease smear to the splines for corrosion protection, but not create a airtight seal as you slide it up in. Check for that and see. Just one of the possibilities. JMHO

 

[94crestliner]

Glad to join you all. I've lurked around on the threads long enough. Plus I'm in over my head on this one...

I did lightly apply a bit of the grease to the upper drive shaft splines. It was supplied in the kit (even labelled that way) and the instructions said to do it. The first time I installed the lower unit, everything went in just fine - I haven't applied any more grease to the splines since then.

 

[flyingscott]

Are the shift shafts jamming up on each other.

 

[94crestliner]

Thanks for your reply, flyingscott. I don't think they're jamming on each other. With that 1/4" gap there's still a bit of room for the upper shift shaft to go down further into the coupler on the lower shift shaft. I'm also able to press the lower shift shaft coupler downward a slight bit more when I push down on it a bit with my fingers.

 

[SteveVT]

Could something have accidentally stuck to the top of the drive shaft and got transferred to the splined recess? Check the recess for that missing lockwasher....

 

[94crestliner]

I was pretty careful replacing the pump SteveVT; everything laid out on the work bench as I took each old part off. I was careful to make sure all the replacement parts were installed as per the instructions both the first and the second times I opened up the lower unit to access the water pump assembly. I took a head count - all the washers are accounted for :^) But I'll re-check in the AM with a flashlight and maybe even carefully run a magnet pick up bar extender to the top of the splined recess area to see if it picks anything out. Its worth a try!

 

[fireman57]

There is an oring that is usually on the top end of the driveshaft on most models. Didn't check yours but on most there is. If there wasn't one on there when you removed it then it could be stuck up there. Go to marineparts dot com and look at their diagrams.

 

[94crestliner]

Thanks fireman57. I had a look at the expanded parts diagram for my outboard's lower gear case (model # E20CRLETS); there doesn't appear to be an o-ring at the top end of the driveshaft. There is a spacer that connects into the water pump housing that has two of them; I'll double check that both are still intact.

 

[94crestliner]

So...I checked the splined recess area with a magnet; nothing metallic is stuck up there. Both rubber O-rings on the driveshaft spacer are intact. I've tried another half dozen times to get the lower unit on, but nothing works; I'm still looking at about a 1/4" gap.

​Any other suggestions?

 

[SteveVT]

Well there's two places debris could be in a splined recess - in the center, and in one of the splines. And on my older Evinrude (not necessarily like yours) there are two splined ends on the driveshaft -- one in the gearbox, and one in the powerhead. If there's debris anywhere, metallic or not, that could do it.

Also there's a shift rod (not on mine -- electric shift) and if that is blocking it maybe it's a matter of shifting and fitting. Finally there's the case itself that may have some kind of interference.

To eliminate the driveshaft and as a problem, try putting the case together without it. That would test the shift rod and case. If that proves out, something HAS to be blocking the driveshaft seating. You just have to find what that is. As stated earlier and also in manuals I have, there is a specific warning not to apply a lot of grease to the shaft ends, because of hydraulic lock, as mentioned earlier -- the only purpose of any grease is to allow them to be slid together easier while assembling. I would wipe most off with a paper towel before inserting -- it just needs a slight bit on the surface. and I would wipe out the powerhead socket end, in case any was trapped up in there.

 

[SweetD]

I had the same problem on my '85 25hp Johnson. Turned out that it was the plastic spacer tube that fits over the drive shaft on my motor - it has a flat side to it at either end - the flat sits into the midsection casting. I didn't have the flat lined up with the housing, preventing it from going that last 1/2" or so into the midsection.

Not sure if your motor has this same spacer tube, but worth a look. Another thing to make sure of is that your drive shaft splines are fully seating into the motor head. You may have to turn the prop shaft a bit while you are fitting the lower leg up in there to get it to align...gotta be something simple like these things...

 

[flyingscott]

If it's the tube that covers the driveshaft put it in first.

 

[clemsonfor]

Is the shift shaft catching on something and binding? While holding the lower in place have you tried to rotate the flywheel to get it to drop in? Bit if it goes all bit last 1/4" it has to be mostly engaged?