1992 Luhrs Motor yacht Drive Shaft Issue

[jws123]

I have a a 1992 Luhrs Motor yacht with 2 454 inboards and velvet drives that I have been working on this is my first inboard I am use to sterndrives. I bought it off local marina was abandoned worked on it all winter had 1 bent strut and 2 bent props fixed. I was told the shafts where fine but noticed beginning of season when it was dropped in the water that one of the shafts has a wobble to it assume its bent. So I have not been running it hard at all mostly 1600 rpm around in the bay because I don't want to bust anything.. I did go up to cruising speed once not really any bad vibration but being a auto mechanic I know what a regular bent or out of balance driveshaft can do to a truck Lol. With that being said is there a spec for runout or something? here is a video I took I plan on replacing shaft next season but getting tired of going slow post opinions below.

 

[Bt Doctur]

Worst case is the shaft will part right behind the coupler flange , the shaft will move rearward to bend the prop blades and maybe the strut and rudder post.

 

[kenny nunez]

Remove the 4 bolts/nuts that retains the coupler to the transmission. Then with a feeler gauge checking all the way around you will be able to see if just the engine needs to be realigned to the propeller shaft coupler or that the shaft is bent. If you can move the engine enough to get the same feeler gauge clearance at all 360* between the 2 couplers, That may be all that is needed.

 

[jws123]

Remove the 4 bolts/nuts that retains the coupler to the transmission. Then with a feeler gauge checking all the way around you will be able to see if just the engine needs to be realigned to the propeller shaft coupler or that the shaft is bent. If you can move the engine enough to get the same feeler gauge clearance at all 360* between the 2 couplers, That may be all that is needed.

I will check this out with feeler gauge when I re installed the prop shafts I don't remember any gaps or anything tho.

 

[jws123]

Worst case is the shaft will part right behind the coupler flange , the shaft will move rearward to bend the prop blades and maybe the strut and rudder post.

That sounds nasty I did put a mark on the shafts to see if they move I keep a eye on it I also check the pins to make sure they stay tight. I just don't want to crack the transmission or anything from what little vibration there is. Is it common or normal at all to have some movement like this? The other side is straight as a arrow tempted to dry dock the boat but its $300 and $25 a day and no telling how long til i can get a new shaft.

 

[kenny nunez]

Why not check the alignment with the feeler gauge before drydocking? Another thing to remember, depending on how the hull is supported alignment can change when the boat is back in the water, so you must recheck the alignment after the the boat is launched.

 

[jws123]

Why not check the alignment with the feeler gauge before drydocking? Another thing to remember, depending on how the hull is supported alignment can change when the boat is back in the water, so you must recheck the alignment after the the boat is launched.

Will check it this weekend with a feeler gauge.

 

[Scott Danforth]

you should not be able to see any wobble

if you see wobble, the shaft is bent.

 

[jws123]

Yea bent like I figured guess I will just take it easy for rest of the season not that much left any ways then get a new shaft before I winterize it.