backed over rope... broke ???
 

last night my driver backed over my fatty surf rope and after we freed the rope from the prop/ shaft it wouldnt go into gear... not sure if the shaft is broke but prop wont turn??? i dont even know where to start to repair it... it's a MB b-52....
if anyone has any tips on where to start i would love to hear them!

Did you try and turn the prop by hand?? Or when you say prop wont turn are you saying you put it into gear and the boat didnt move?? I cant believe it would break the shaft or tranny. I would bet it broke the keyway were the prop goes onto the shaft. I would try to turn the prop by hand and see if it is spinning free on the shaft. remove prop and inspect keyway. If you have ?? call me 727-434-1191 my name is Kevin. I am a boat mechanic and might be able to point you in the right directon.

There is a chance that the key is broken. There is also a chance that the shaft is broken. On MB's it can be difficult to tell if the shaft is broken because of the rigidity provided by the strut and drip-less packing that effectively locks the shaft into place.

Alan educate me on what is so different from a MB set up as opposed to a tige or malibu. I am not sure what you are trying to say. If a prop shaft broke frombacking over a rope thats pretty ****ty.

There are many different types of drippless packings that are used in inboards these days.

Off the top of my head. MB, Tige, Correct Craft, and Ski Supreme all use PSS drippless systems. I believe it is the best design although I am sure that somone will argue with me about it. But in the case above (Potentially a Broken Shaft) they serve a second purpose. The PSS system works by using a stainess collar that is attached to the shaft and compresses a rubber boot that is capped by a ceramic ring. The pressure between the stainless collar and ceramic ring, shut out all water and stays cool due to the minimal friction that is created.

The "secondary purpose" they serve is keeping everything in place in the event of a broken shaft. Most broken shafts I have seen occur right at the v-drive or transmission. In this event, the stainless collar and rubber boot keep the shaft in place rather than getting yanked out of the boat and causing a 1 1/8" hole in the bottom of the boat from the shaft falling through the boat.

As far as the actual shaft breaking. It happens sometimes and most of your underwater gear is made by Marine Hardware, INC. Has nothing to do with MB.

Keep in mind that some MBs, like my 2005 B52 V23 use the PSS but in a different configuration than pictured(no cooling hose as pictured).

I had a bent shaft that caused the key way to break, the tranny seal to gape and puke fuild into my bilge and eventually I had water gushing in through the bottom of the boat (thank you insurance for fixing everything...).

The only visible damaged below the waterline was one blade of my prop that was very slightly bent. Weird stuff.

The water line going into the ceramic cap is not necessary in all applications. The primary purpose for that is when there is an awkward alignment issue. You won't see the hose in most ski or wakeboard boats. Your shaft bending and causing transmission damage has absolutely nothing to do with the packing gland used, I assure you.

last night i pulled off the coupler at the front of the transmision and found a broken key at the tip of the shaft, also when i pulled the coupler off the shaft was pulled to one side of the opening... after geting under the boat it appeared that the strut under the boat that holds the shaft may be a little tweeked.i had someone spin the prop while i looked down the shaft it apears to be strait still, but not sure if i should order new strut or jus try to bend it back with nylon straps...
thanx for all the help and opinions.... alot better than calling MB!

Good to hear. Keys are a lot cheaper than shafts. :)

yeah so i got a key , pulled the shaft rolled it on the straitest surface i could find to make sure it was strait.... if it was tweaked my eyeball cant see it. but when i put the shaft and stut back on it comes through the transmision centered but when u look at it from the back of the boat it isnt centerd going up through the boat. my shaft still may have a slight tweak.....
any thoughts?

Whats the 3/8" hose going to the shaft?? Dampener?

I personally don't understand why some applications want water going through that hose. Most ski boat manufacturers don't use it. It is strange to me because the "rubber boot" and ceramic ring don't touch the shaft at all. The only contact is between the stainless collar and the ceramic ring, which has constant water pressure on it anyway.

Russ, sounds like you need an alignment.

Yep, sounds like an alignment and/or a new strut/cutlass bearing is in order. If you bent the strut, you have to replace that before it can be aligned.

That was one strong rope!

I have seen a specra line break a FCT 1 off of a super air from getting wrapped around a shaft.

Russ,

Are you are saying that the shaft doesn't go through the center of the hole in the bottom of the boat (the 'log')?
I think that it is pretty common that the strut doesn't line up in the exact center of the log.
As long as the strut doesn't rub against the side of the log, no problem, I think.
It's a quality control problem. Cleatus may have been a bit hungover that morning when he took the hole saw to your hull. :p

The important thing is that the strut, transmission, and engine all be in alignment.
You may have to take the shaft to a shop to see if it is bent.

If, after placing the coupling nut on the shaft, the coupling nut & transmission line up, with the coupling nut not left/right, up/down from the transmission, and you can rotate the shaft with no change in this relative alignment ('wobble') than I would say that you are golden!

If it wobbles, get the shaft checked out, it may be bent.
If the shaft is not bent, the strut is.

I wouldn't try to bend the strut to get it to align with it still mounted on the bottom of the boat, though! :eek:

If the strut is slightly bent, the easy answer may be to remove it, and shim it with something like stainless steel washers.
I say easy... I might have meant cheap...trying to figure out exactly where to put that one golden shim may drive you nuts! :rolleyes:

You need to do a shaft alignment, I am sure there is a thread or 2 on that on WW,
on my MC it is supposed to be within .003"... not much, about the thickness of a sheet of paper.
basically you separate the coupling nut from the transmission a little, and measure with feeler gauges the thickness all around, and if the difference is more than .003, loosen and move the engine/transmission mounts a bit.
You are done when you can rotate the shaft, and the measurement all around is less than the spec.

You may want to replace the cutlass bearings in the strut while you have the shaft out...
I'll leave the brass vs. vesconite wars to another thread! ;)

Hope this helps!

David

P.S. I am no expert, so someone please chime in if i've got something screwed up!