Prop Shaft End Play

[Pontoonarama]

Hello all, I did some searches first, but either I couldn't find an answer to my specific issue, or the posts were several years old and likely wouldn't garnish much attention by posting my questions there.

My wife and I recently purchased a 2004 Odyssey 18' pontoon with a 2001 Mercury 50HP 2-stroke. On our maiden voyage, everything went great for the first 10-15 minutes at (near) WOT. Then we slowed down, got our bearings to change course slightly, and when we tried to resume accelerating, it would pop out of gear, followed by the engine revving up and a fast grinding. Immediately pulled the throttle back, and we could hear it lock back into gear. Would accelerate fine up to maybe 30-40% throttle and then it would happen again. We nursed it back to the ramp and brought it home.

My internet searches pointed to a worn out clutch dog/gear teeth, poorly adjusted shift cable, or a bad prop hub. I figured that since we could hear the teeth chatter, it was not likely the prop hub. There were also traces of oxidation between the prop and hub, so I feel like if they were to be spinning in relation to one another, that oxidation would have been worn off and there would have been "some" trace of the two spinning. I took the entire lower unit off and apart and the clutch teeth looked brand new. Also, the forward and reverse gear teeth also looked equally as new. With the help of my wife, I checked the orientation of the vertical rod (blanking on the name right now) that pushes the clutch dog back, and it looks to be traveling perfectly between all 3 positions. Then, while scratching my head and putting it all back together, I noticed the shaft play...

I wish I would have just taken a picture instead of trying to explain all of this, and I am considering drawing a picture, but basically, with everything bolted in place, you can grab the prop (which is pinched between the splined washer and the castle nut pretty solidly) and push it into the lower unit by about 3/16". This moves the entire shaft into the lower unit by 3/16" as well. I took it all back apart again to see if there was a washer or something missing, but I don't see anything missing. I looked at parts diagrams online, but there is nothing shown in them that I don't have on my prop shaft. The cause of the play in the shaft is because when the shaft is inserted through the reverse gear and "carrier" (also not sure the proper term for this block of metal with the bearings in it) and it pokes out the other side so that you can put the splined washer and prop on, there is a gap between where the splines end (and the splined washer sits) and the carrier bearing. This allows the shaft to move back towards the front of the lower unit, until the splined washer hits the seal for the bearing in the carrier. When this happens, the small "bulge" in the shaft where it stops against the reverse gear, moves away from the reverse gear. In theory (at least as far as I can think of it in my head, this should effectively move the clutch dog closer to the forward gear, and engage it more. However, when I put it all back together, and put the gear selector to where the prop JUST locks onto the forward gear, I am able to push the prop into the lower unit that 3/16" with my hands and disengage it from forward gear. Trying to figure out why this is happening, the only thing I can think of is that the pin at the end of the shaft is too long, and when I push the shaft in that 3/16" it is actually pushing the clutch dog back on the shaft. I just have a hard time thinking that this thing ended up with the wrong length pin in it....

If any of y'all have any ideas or suggestions I would greatly appreciate it! I am kind of at a loss here and not even sure what else to check... I think we're going to go pick up a new prop either way, just to be safe, and because I've seen a lot of recommendations to have a spare on hand anyways. I'll put the new one on and take the boat out again Memorial Day weekend, and maybe the whole "taking everything apart and putting it back together again" thing fixed it... It works sometimes loll

I appreciate you all!

Justin

[curtiscapk]

like this? posted last week..
viewtopic.php?f=2&t=26612

[Pontoonarama]

like this? posted last week..
viewtopic.php?f=2&t=26612

Yea, basically like that lol... I wish I could figure out how to search these forums better.... This happens literally ALL the time. Guess I'm back to the drawing board on what caused my issue then...