YSM12 Coupler - Diagnosing a Potential Problem

[Mighty Little]

druid - I don't know the answer to why. something from the PO is all I know. there's no damage to the prop or keel or really anywhere on the hull that would suggest grounding. my hunch is that it's all original hardware and age has simply caught up with it. I assume that's possible - but I really don't know what I'm talking about here!

Here's the fixed condition. Drivesaver will be re-installed on the hard when we re-do the shaft. I'm operational for now!

 

[sesmith]

Always blame the PO Seriously, all it takes is someone disassembling the coupling and putting it back together without having a machine shop fit and face a new coupling for the installation.

We had a similar situation. Previous owner told me he replaced the PSS seal. Great, I thought, at the time. That is, until a year or so later when the coupling loosened up. By the time I caught things and learned more than I wanted to about couplings and engine alignment, we had to replace the prop shaft, coupling, and cutless bearing, while we were at it. I also got to replace the PSS seal again because he had put in the non-vented version, which periodically trapped air under it. I put the newer style vented version in. No problems since.

 

[Mighty Little]

In case anyone was wondering the "quick fix" on the prop shaft coupler towards the latter part of last season turned out to be a disaster. Well, that's a strong word, but it did shear straight off again and left me stranded and drifting in a crowded mooring field full of shiny new charter boats. Uh oh. Kindness of strangers and all that and it turned out me and the family were safe, but after getting the boat hauled and inspected properly I heard from the new (and awesome!) mechanics that they were able to remove the entire prop shaft through the back of the boat WITH NO TOOLS. Simply slid right out. I nearly passed out when they told me, and they promptly suggested I go buy a lottery ticket as I seemed to be one lucky dude.

Over the winter I had them replace the entire coupling, prop shaft, stuffing box and cutlass. I stuck with the original prop, not wanting to drop any more money into this particular solution. We have been 100% operational and having a blast on the boat this summer. All in all a great (if moderately expensive) learning process.

Stay safe out there...!

-ml

 

[Tally Ho]

!

From this photo, it looks like:
1) you don't have any set screws in the coupling. Maybe they they are hidden on the back side, but there is a big hole where it is supposed to be (there should be 2 set screws)

2) there appears to be a wear groove (must be pretty deep if I can see it from the photo) in the shaft just behind the coupling.

Do you know if the shaft sheared off at that spot?

I replaced the shaft on my O'Day 322 this past winter...here are a few videos of the process.

- coupling removal

- shaft removal

- shaft installation

Greg

 

[Mighty Little]

Greg - the pic you're referencing above is the quick-fix condition that ultimately failed, in somewhat dramatic fashion. We've since replaced the entire thing.

 

[Ken13559]

Are there 2 locking screws on the hub of the shaft side coupler? These screws are usually lash with steel wires to prevent undoing itself while the coupling/shaft spins.

 

[MitchM]

when you go to get the new p shaft made: get OEM dimensions of shaft length, taper, propeller mounting thread, and key design. i spent 2 unnecessary months on the hard in 2009. an incompetent travelift operator hauled before the signal and caught the aft end of the p shaft. i ordered a new p shaft from a ' highly recommended' fabricator. the shop got my damaged p shaft -- PLUS engineering drawings on shaft length, diameter, taper, key design etc. from my boat manufacturer. the shop sent me my old shaft and a new one that was (a) too short by an inch and (b) the wrong taper. I still have the photos of that inexcusable $690 disaster -( explanation: ' new guy on the machine...') i refused to pay the bill. they told me to keep the bad shaft... which is usable as a stainless steel expensive. porch railing.