shaft length compared to other side, motor mounts adj

I've been working like a madman to get back in after I hit "something" a couple of weeks ago. Rudder and strut were straightened, new shaft and one prop fixed and the other checked since I had the boat out.

I have everything back together but have two potential snags:

1) After I installed the new shaft, I noticed that the distance between the back of the strut and the back of the prop looked different. I measured the other side and sure enough it's about 7/8" - 1" difference between the two - the distance on the new shaft is longer. I then measured from the end of the shaft to the rudder and it's about the same difference.

Thinking that maybe the prop wasn't on as far as the other side, I compared how much of the shaft extends past the end of the prop and it's a difference of maybe an 1/8" between the two sides. A slight difference but not enough.

The shaft is in the right spot on the coupling end unless they milled the set screw hole in the wrong spot. It sits flush so I don't think this is my problem. I'm starting to think maybe the shaft is just an 1" too long or the taper isn't quite right and the prop needs to be farther back.

Would you guys worry about it? I can't imagine that an 1" would make a difference in steering from one rudder to the other. I don't know if it would make a difference at speed. I really don't want to take the shaft out again if I can avoid it.


2) I think I'll need to drop the back of the engine when I do my final alignment but one side is at its limit on the mount. Can I just remove the metal shim that there's there and replace it with a thinner one?

Does Crusader sell an engine mount shim kit with different thicknesses?

I think I have the rough alignment good, the prop spins easily with one hand and the shaft is pretty well centered in the shaft log.


Bob

I'd remove the set screws, knock the coupling on another inch, then drill new holes setscrew holes. Wrap duct tape around the drill bit to protect the coupling threads.

Aligment is a b*tch! You do what you have to do to get it right.

jeff

Jeff, I have a spilt shaft coupler (nut/bolt on each side) and one set screw. I would have to check and make sure there's enough clearance for the add'l inch so the flange and coupler can bolt back together. Might be an option though.

The set screw goes into a dimple on the shaft. It's gotta be pretty tough drilling into this type of SS right?

Ihave a recent story on my new, split coupler. We were fishing some 80 miles out, and the bilge started to pump, and didn't shut off very long, and pumped some more. Turned out, that single set screw in the coupler worked its way completely out, and the prop shaft moved forward an inch. That movement caused the DSS seal to leak big. I did a jungle fix out there that stopped the leak, by moving the DSS ROTOR back an inch, but would really like to saftey wire the square head bolt. My original coupler had two setscrews, each saftey wired. I suppose I need to hand craft some set screws with holes..

I'll bet the shaft was not drilled for the points of the setscrew to enter. THAT is what keeps the shaft in place.

Jeff

locktite 271 will keep the setscrew from moving. If you want the safety wire, find somebody that works (or used to) on aircraft....they use it all the time and should have some pre-drilled set screws.

If you have the space inside the coupler, you can move the shaft deeper. If you move it, you'll have to 'spot' the shaft. Use a titanium bit, plenty of lube, and keep the drill bit rotating SLOW. It won't take long at all if the bit is sharp. If you don't have that bit, buy one - you'll make it back the first time just by the time not wasted. I've found a hardwood dowel in the set screw thread does well protecting them. I believe 1/8" is plenty.

I don't think the inch will make a big difference as long as thing are assembled ok. One thing I've learned is very rarely are two props bored the same - they all seem to rest on the shaft a little different than their mate. Also, not uncommon for the struts to be offset a bit - fore & aft - from each other....same for the engines.

ok, thanks guys. It might have been this way since day one but I never noticed (if it changed) until now. I'm going to try and re-launch today. I know the alignment is off, maybe I can putter around the harbor for an hour and work on that in a couple of days.

Locktite and / or lockwire will only keep the setscrew from unscrewing. The drilled dimple in the shaft is what keeps the coupling from moving.

Jeff

Well, I found the extra inch last night when we did the alignment. It seems obvious now but I never gave this possibility a thought.... the engine got pulled back from the impact.

As soon as I looked straight down, I could see the outline of where the rear mounts were located. Fortunately, the mount bolts are slotted in the bracket so the whole thing just pulled back. I guess this was a good thing because it took up some of the impact instead of a hard stop if they were through bolted. That might have broken the bolts, mount or maybe the transmission.

We loosened everything up,pried it forward and then did the alignment. Hopefully I can sneak out for a test run tonight.

Bob

Bob:

Glad you found it. I know that things like that will take away from sleep and other essential activities. Hope it all works as planned.