Got another shaft coming.  Like the one in the (This one works) picture.  For all the fuss and bother I’ve put into a (spare) lower unit, LOL, I felt it was worth the price.  We’ll see what happens with that.  Dave-Bernard brings up the possibility that the depth of splines in the pinion gears might be different.  He may have a point there.  All I know for sure is that at one time this unit worked, kinda.  It turned properly, but was defective.  It was purchased to replace a lower unit that wouldn’t stay in forward gear because of of a worn clutch dog/forward gear lobes.  Turned out the replacement lower unit had the same issue, so I began to tear them apart, figure out how they work, and slowly attempt to find parts and get them all back together.  One of them got a new drive shaft.  I just now dug up the old one and it matches the one that works.  I think this will fix it.  I won’t try to put the old one back in to test it out as I don’t want to risk damaging the seals with this ragged old shaft, but I think I see light at the end of the tunnel.

Mumbles,

This is true.  But in this instance I believe I installed an incorrect shaft, possibly had the washers in wrong, sealed it up and called it a day without every checking to see if the shaft would turn.  Now, after over a year, I discover the driveshaft was frozen solid.  We’ll see what the replacement shaft does.   Should be here by the end of the month.  I have a good feeling about this.

Now, I’m really curious as to what a brand new, newly manufactured, high quality drive shaft of this sort would bring on the marketplace?

fleetwin.

You are right.  I have no idea why changing the driveshaft would help.  Lol.  And it didn’t.   I too have had posts disappear before I could actually post them.

Today I tried the new shaft.  It made no difference.  I also tried removing the rear oil seal pin, just in case it was too long and elevating the seal housing.  It seemed to make some improvement, but when I tighten down the last little bit, it seizes.  It gets harder and harder to turn as I tighten it down, and I want to note that as it begins to become harder to turn, I can feel a rhythmic pattern to the vibration which I believe is the gears meshing together excessively with the pinion.  I have not installed the new washers yet.  Not expecting much from that but will give it a try.

Considering I was unable to find anything on the skeg rubbing on the drive shaft assembly with the carbon paper, I am trying to come up with a different way of determining where, if any, unwanted pressure is being applied to the driveshaft assembly when the skeg is tightened down.  Since everything turns very nicely without the skeg on, and the pinion and gears look very well married to each other, I have to believe the skeg is applying force to some part of the driveshaft/gears to be causing this.

Bottom line is that I should have all the correct parts installed.  I’m tempted to crack the other, working, gearcase open and try to see exactly why it is working.  I probably had both of these apart at the same time and may have swapped something out that I shouldn’t have.

• This reply was modified 2 years, 2 months ago by boscovius.

It’s a 25028.  I know for fact that it is not the original lower.  I had a guy work on it for me back in the day and instead of just fixing my lower, he just swapped it out for another without consulting me.  Not cool.

It’s a bit a a Frankenrude in that it has had a starter and electric start flywheel added to it.  Between this lower and the other, working, lower, I have no means of knowing if parts were switched out between them.  I would guess they have been.  However, as far as this troubled unit is concerned, the prop shaft is near mint condition.  New clutch dog.  New front and back bearings.  New needle bearings in the housing, new pinion.  New pinion bearings. The gears look very new.  Though I do not remember replacing them.

I have yet to install the new thrust bearing washers.  I’ll try that next.  Probably tomorrow.  And I’ll try what you said about trying one gear on, then the other, to see what effect that has.

Something to keep in mind is that when I first started working on this, Marine Engine was my only resource at the time and because they don’t have a schematic going back as far as my model number I used the RD-19 for all my parts sourcing as it looked like a good match.  I do have the correct schematic now.  But as far as I know, most of these parts don’t have numbers engraved on them so it’s anyone’s guess as to what I have now.

So where it stands is that with everything installed except the skeg, everything turns freely via the driveshaft.  In forward and reverse.  Put the skeg on 99% of the way and it still moves, though a bit rough.  Tighten it down 100% and frozen solid.

Thanks for hanging in there with me so far.

Yeah, like I was saying,  since I had both of these units torn apart at the same time, I probably swapped things around.  Unfortunately, this may complicate things.  I think if I open the other one up I’ll be able to get a better idea of what’s going on.   I’m not opposed to spending a little more money on, say, a matched set of gears, if that’s what it’s going to take to make this right, but hopefully I’ll get lucky and figure out a cheaper fix.  My wife just got a very expensive puppy for her birthday.  I have my own needs.