1956 Evinrude Fleetwin 7.5 hp - drive shaft looks funky

[BurnipsBandit]

Hello, I am new to this site as far as posting, but I have enjoyed reading the posts the last year or two. Now I have an issue I hadn't seen anything about.

I have an old 56 Evinrude Fleetwin 7.5 hp that I bought off a dude from work for $100, as he was moving and didn't have space to bring extra stuff. The first few years I had zero issues with it. Last year I noticed that it would seem to pop out of gear while attempting to accelerate. I could go slow with no problems, but as soon as I give it the juice, the engine would rev up nice but the propeller seemed to just quit working until I slowed back down and then it would re-engage. I also drained the gear lube as I assumed that water was getting in there and creating friction, allowed the gears to seperate.

As I suspected, water was getting in. I bought a new seal kit/impeller/shift rod bushing and some bad ass 3-M sealant, sealed it up, got on the lake a couple days later. Same thing.

I gave up at that point, until today. I took it apart and kept the lower unit together, submerged in stages, it wasn't until the impeller housing when I started having issues. So I will try to seal that up better tomorrow.

But I did notice that I had some rings on the top portion of the driveshaft. I never noticed them before. The teeth had a little wear but not like something you'd expect to jump out of gear on. I'll try to attach a picture so you can see what I am seeing. Is this what is causing the gear jump as well? The area where the shaft slides into in the motor looks good, I would dare say it's a hardened steel.

Anyway, short story long *, thank you for looking

 

[racerone]

Where are the parts for the mechanical seal that fits at the top of the driveshaft.--------It sure looks like it was not assembled correctly there.---Spring was bouncing around in there.------And no that is not the reason it was jumping out of gear.----Have you looked at the clutch dog / forward gear ?-----Have you inspected the shock absorber ?

 

[BurnipsBandit]

Where are the parts for the mechanical seal that fits at the top of the driveshaft.--------It sure looks like it was not assembled correctly there.---Spring was bouncing around in there.------And no that is not the reason it was jumping out of gear.----Have you looked at the clutch dog / forward gear ?-----Have you inspected the shock absorber ?

I've got the parts, they were brand new when I replaced the seals last summer. That is exactly the area where the marks were on the driveshaft. The only thing I can see as a possible issue for that could be the small retaining pin on the driveshaft where that shock absorber sits. It was a little further to one side than the other, but I could not get it to move enough to even get into position to make marks like that. I'll attach a picture of that

 

[BurnipsBandit]

Also think I found my water leak into the gearbox, the seal on the bottom side of the plate for the impeller had deteriorated, so just like the movie Gremlins, I got it wet and it became two

Also got the gearbox cover off, didn't get a chance to clean up real well as it's now after midnight. I didn't notice anything funny for the most part, the gears don't look bad to me, maybe I'm wrong but they look ok to me. Clutch dog pieces were all there. I did notice some marks on the bottom side of the driveshaft where it meets the smaller driveshaft. Looks like the same type mark, just off 180° from each other.

For some reason I can not upload any pictures right now, will try again tomorrow

 

[fdrgator]

That motor looks like it ran for a lo-o-o-n-g time with a bad seal. That lets water into the crankcase. I'm surprised it hasn't tossed a rod yet.

Wear marks on the bottom end of the drive shaft, at the top of the flats, are normal.

 

[BurnipsBandit]

That motor looks like it ran for a lo-o-o-n-g time with a bad seal. That lets water into the crankcase. I'm surprised it hasn't tossed a rod yet.

Wear marks on the bottom end of the drive shaft, at the top of the flats, are normal.

I am sure it had water running in there for quite a while. When I noticed it and replaced the seals, the seal at the propeller shaft was in bad shape, the seal was toast. Fishing line wrapped up in there...classssssic.

I added a couple pictures of the drive shaft where I can see marks on it where it goes in to the smaller driveshaft into the crankcase.

 

[BurnipsBandit]

Alright guys, I had to move the picture files to the computer and resize them to allow the uploads to go thru.

Got the crank case apart last night, it's still a little dirty but the gears did not look too bad to me. If they look worn to you, let me know please






This is the area I was talking about with the rings on the shaft. If you look close, you can see that pin thru the driveshaft sticks out to the left more than the right, so it's offset. I could not get the spring/seal/washer to move around enough to even get into position to make marks in the area where they were made. I do not doubt this is what caused the rings tho. There is some play in that bronze washer on top, but I suspect it's like that for a reason, it seems to sit on the rubber o-ring in the black plastic piece just fine. Again, this whole assembly was new as of last summer, with no more than 2 hours of run time on it (only 2 hours as this was the time I tried it on the lake, it still jumped out of gear, so I had to fish, OF COURSE, and slowly put back to the dock lol)



This is the piece below the water pump, driveshaft slides into it and the other end is keyed with a gear on the end. Driveshaft extension? Lower Driveshaft? There is a washer in the middle there. Now when I took apart the lower end, the key and gear were intact, seemed to be in the correct spot, but maybe the gap in the middle of this piece is not correct? spacing? It looks like a pin goes thru it, so it should be a fixed location/length.



So it feels like if the driveshaft is moving up, allowing this to kick out of gear, my failure point would be either....
A. That gap is incorrect on that lower driveshaft
B. The Upper portion of the driveshaft pushing up in to the motor (is that even possible?)
C. The gear that is keyed on the lower driveshaft is worn out


here is another picture of the propeller shaft/gears/clutch


Thank You guys!

 

[BurnipsBandit]

Looks like the clutch dog has some rounded off edges, seems like that would be the source of the problem currently. The gears look hardened so the rounding there is minimal.

Too bad I can't just flip it around 180°, other side is exactly the same for the reverse gear just not as bad

 

[fdrgator]

When I said that has been run for a long time without a good seal, I was talking about the seal at the top, under the powerhead. I figure it was before you got it.

That wear at the flats area is normal--as I said. That short shaft that it goes into is called a shock absorber. It has a very strong spring inside, which is prone to breaking. When it breaks it either slips or locks up everything. That might be your slipping problem.

The off-center pin is of no concern.

 

[fdrgator]

delete

 

[bobbyc]

Some of the clutch dogs on the older motors were flip able...if it hasn't been done already. Be sure the linkage is properly adjusted!

 

[racerone]

????----The driveshaft moving up has nothing to do with it kicking out of gear !!----And BobbyC---The beauty of these gearcases is that the shift is factory set and there is no adjustment that can be messed up.

 

[BurnipsBandit]

Nice, I will check into that

Thank you for the diagram, I had no dea there was a spring in there.

 

[BurnipsBandit]

Some of the clutch dogs on the older motors were flip able...if it hasn't been done already. Be sure the linkage is properly adjusted!

It's worn on both sides, same spots, flip it and it's a mirror image, no dice. But I do have a new clutch dog coming in the mail along with a replacement gasket for under the water pump. $11.00 total and free shipping, not bad, now to just wait ����