super sport/air shaft repair & cutlass bearing

Hi Fans,
Long time reader, first time post.

Summer is approaching fast here in Australia, so i got a few jobs done that I've been putting off for a couple of seasons.
The prop shaft in my 2002 had a slight bend in it towards the coupling end, you could watch the stuffing box wobble when in gear at idle. The shaft packing was leaky, after adjusting the nut, it would start to drip excessively after only a short period of time and the rubber log hose was swollen due to old age.

So i pulled the rear seat, floor and ballast pumps, then the rudder, removed all the coupling bolts, loosened the safety collar then went ahead and removed the coupling from the shaft. I used the spacer & long bolts method with slight tapping from a hammer. Being under the V-drive access was difficult, but still only took around 1/2 hour to remove.



The cutlass bearing had slight play, not as bad as i expected for 800 hours but i ordered new bearings while its apart and for proper alignment on re-assembly.

After putting the shaft on some make shift V-blocks with dial gauge i measured it was over 4 thousandths out.



I marked the high spot on the shaft and used a shop press to put pressure opposite the spot i marked.



I spent quite some time back and forth checking, marking, pressing........



After about an hour of this, i was able to get it to within 1 thousandth, i couldn't get any better as the high point would just keep moving to a different spot and i was chasing my tale. (excuse the metric gauge)



Once the shaft was done i removed the old cutlass bearings from the strut using a hack saw to cut a slot through the shell then a hammer and chisel to tap them out, I then cleaned up the inside of the strut and installed the new bearings. My strut had two 3" bearings from factory so i just replaced with the same. I ended up using composite shell cutlass bearings from my local store ('Exalto' brand)



Some threaded rod and large washers done the trick to pull them both in nicely. I marked the shells so i could line up the channels of each rubber bearing.



Prop shaft went in with new 3/16" GFO packing, fresh bolts & log hose. I warmed up the shaft coupling for a bout an hour in the oven and it slipped on nicely.



Then onto the alignment, I raised the front motor mounts 1/4 turn at a time until the alignment was spot on...... then bolted it all up. The shaft spins freely by hand now, unlike before.
The rudder also received some new GFO packing (1/4") when re-assembling, that and some fresh grease.....steering is silky smooth.



I water tested it before re-fitting the back seat and ballast pumps etc. At first i had the shaft packing nut a little tight, it was getting hot after running around for a bit. I found out with this GFO packing the nut really only needs to be barely hand tight. After adjusting a few times it ran like a dream, and the shaft now runs dead true. Ready for another 800 hours i hope.

Nice work. That is quite a unusual spot to have a bend in the prop shaft.

Mark and Jim,
I'm going to take a guess as to why the shaft is bend in that location. The boat was set down on the shaft just aft of the log at one time. I've seen it once where a owner stored his boat on timbers across the wet slip in a boathouse and didn't block the hull correctly. All the weight of the aft end of the boat was placed on the shaft.

Pete my first thought for trying to explain the bend in that location, was misalignment over a long period of time.

SNobsessed wrote: I hit a submerged log & it bent the shaft (.010 inch) in same area (between strut & coupler). I think the log wrapped up the drive train. Hard to believe, but it didn't damage the prop. I was able to straighten it (to .003 ) in much the same manner as Muzz .001 is very good!

Good to hear....

Yes I was quite happy with .001 , although it was ALOT of back and forth measuring & pressing.....

Gary, what other 7-yr period didn't come along with significant change in details?

That prop to strut clearance looks pretty excessive from this angle... You sure you don't have one of those vibration dampeners between the couplers? We ran about 1/4" prop to rudder clearance for a while on the BFN and it didn't seem to affect much from a performance standpoint... Not sure I'm crazy about the proximity long-term though.

Yes the raked acme will extend much farther back. Measure your strut to prop clearance when you can. Nothing the same about pylons or tanks from the eras you mention...

Thanks for the post Gary, interesting to compare them back to back like that.

I grabbed a couple of pics showing my prop to rudder clearance.

This one is my Acme 380



And this is my OJ



Both of these are approx 1" prop to strut spacing.