Spring problems re. drive and prop shaft

[Shrek]

Hi All,
Haven't posted for a while so here goes.
Yesterday I had the Columbia 30 (1972) pulled out for a quick powerwash and underbody inspection. On the way to the lift following a good warm up and the ability to get over red line RPM's on the tach. (momentarily) I put the beast into forward gear and immediately noticed that I was not developing full rpm on the motor when in gear.
I thought that perhaps a good cleaning must be needed and this was confirmed by the amount of caked on sludge on the hull and the amount of barnacles removed from the shaft and prop.
The lift operator also noticed after cleaning it all off that I have about 1/8 inch of longitudinal play in the prop shaft when it is pushed in and out towards the v-drive and engine direction. Is this a big issue and how do I go about adjusting this. Walter v-drive installed.
Anyways, this issue with the drive in gear, did not disappear after the cleaning, and even on the way back to my slip, it felt like driving a car with one foot on the gas, and the other foot partly retarding everything by pressing on the brakes at the same time.
When in neutral you can easily turn the prop and shaft by hand with no feeling of retardation, so where is my issue? Could it be that an adjustment of the v-drive is required (slippage?) This did happen one time last summer, but when I did a test run with my mechanic minutes later the problem was gone. now it has come back. The engine is behaving itself and is running within oil pressure and temperature specs.
Help appreciated !

[Al Schober]

Shrek,
Doubt if this longitudinal play is in the V-Drive - they're pretty solid.
First thing I'd check is whether the shaft is moving fore-aft in the shaft coupling. Could be as simple as a loose set screw. Certainly something you want to fix before the shaft pulls out of the coupling in reverse - I've seen it happen! The shaft should actually have a small divot drilled in it for the set screw. Relying on the set screw to bite into a smooth shaft is VERY iffy.
If your shaft is moving in the coupling, I'd recommend loosening the screw and pulling the shaft out of the coupling and examining the spot where the set screw bears. If there's no drilled recess in the shaft, you've found the problem. Hopefully you can drill it in place without pulling the shaft out of the boat.

[Shrek]

Al,
I assume there should be no longitudinal play in the shaft on the output end of the v-drive.
I will be back down there to check on this tomorrow.
Looks like I might have to pay for another lift ???

[Al Schober]

Shrek,
Correct - there should be NO longitudinal play of the shaft in the coupling. There also should be no radial play (looseness in twist) but there should be a key to take care of that.
As I recall, that set screw has 5/16" threads and has a 1/4" nose - so the shaft should be drilled with a 1/4" bit at least far enough to get the full 1/4" diameter in the shaft. You're not trying to drill thru the shaft - just a conical seat for the tip of the set screw.
Loosen/remove the set screw and slide the shaft out far enough to see what you have - if there's already a divot, you're good. If not, slide the shaft back in and use the female threads of the set screw to guide the 1/4" bit into place and drill a divot. Reinstall the set screw, snug it up, install some lock wire to keep it from backing out, and you're good to go.
Plus, you'll have the satisfaction of knowing you've done the job right. This is more than 50% of the waterfront mechanics will do - too many will install things without the divot!
Whether you have to haul and pull the shaft is up to you. Yeah, doing the job in a drill press is nice. Working and getting the job done in place gives me the warm feeling of having saved the haul charge. If your position for the job is uncomfortable, a cushion for your back and a pillow for your head will make things a lot better - perhaps even tolerable.

[Shrek]

Have not been to the boat yet - but it will be soon. You have explained this beautifully and from memory I think I can do this easily as The shaft will not fall out of the tube as the 2 zincs will stop this from happening if they even reach the strut with the cutlass bearing. I will post again when I have found the issue. Hopefully this is the cure. Thanks again.

[JTG1160]

Very Helpful

This trail was very helpful during a recent issue where my shaft backed almost all the way out of the coupling in reverse. Thank you! Two questions, how tight should the set screw be set into the divot? Crank on it pretty hard? Of course have also put the wire in place as well. Second question is that in order to get the shaft back into the coupling I ended up diving under the boat and tapping the shaft back in with a hammer (light taps). Was able to get it back into place with the set screw aligned to the divot (why these divots aren't deeper is beyond me). Afterwards took the boat for a spin and seemed to run well. But any concern on how the shaft was put back in? Thanks again! These forum topics are amazing.

[Al Schober]

JT,
I like the German torque specification - 'gutentight'. Seriously, snug will do it since the divot in the shaft gives a physical interference. You're no longer relying on friction. In addition to the wire, I'd use some blue loctite which can be removed later without needing heat (like the red stuff).

[ndutton]

Was able to get it back into place with the set screw aligned to the divot (why these divots aren't deeper is beyond me).

Then drill them deeper. I've mentioned it before, I used to dress the inboard shaft end so the coupling could be slipped on by hand but that meant relying on the set screw(s) to keep the shaft in place so I was pretty aggressive with the drill press.* And yes, crank the set screws tight.

Hammering a shaft into the coupling attached to the engine transfers all the impact force to the driveline components and risks damage. Good on you for recognizing that per your report, "tapping lightly."

*Never had a shaft back out

[Shrek]

apologies

Just got an email from the list today from a member who found this thread re. how to take the play out of a loose propeller shaft. it looks like I forgot to reply to all who gave me good advice some time ago re. the cure.

I did indeed find that the set screw was loose and had no wire fitted to prevent it from coming out completely. It was my mechanic who noticed this during a haul out for cleaning.

I tightened the set screw into the divot, installed s/s seizing wire and the problem was solved in a matter of minutes.

Belated thanks to all who advised and thanks to Don Moyer and his company for this wonderful group of owners who constantly advise on all matters Atomic etc. etc. etc.

Gordon Foster, Vancouver, Canada