Revolt 30 - bushing question - 1st post!

[4mulafastech]

(I posted this in the Revolt forum, but thought I would put it here to hopefully get more views and advice.)

I have been doing a lot of reading on OSE. Great forum and I am so glad I found it! I decided to get my first FE mono hull, a Revolt 30. I am very happy with the performance. I have S&B the stock prop and the larger 45x68 GrimRacer prop. I have tweaked the strut height, trim tabs and turn fins. Awesome performance and really flys with the bigger prop!

Now the question. I have upgraded the flex shaft and I noticed I lost some speed. Brough it in and saw that the bushing backed out of the strut and was touching the drive dog. The instuctions state to have 4-5mm distance from the drive dog to the strut. The larger diameter (collar) of the bushing is only 3mm long and the picture shows the drive dog 4mm from the strut. This situation will allow a lot of wobble and I believe was the cause for the slower speeds. I have read on here that the bushing is a 'floating' design and should spin in both the strut and around the cable. What is the solution here? Should I run with the drive dog closer to the strut, like 2mm to prevent the bushing from backing out too far? Thanks for any help you guys can provide!

I also included a pic of my Revolt 30 and GrimRacer prop balancer.

bushing.jpgwaxed1.jpgprop balancer.jpg

[4mulafastech]

I did a lot of searching and found a good thread related to this subject:

http://forums.offshoreelectrics.com/...light=floating

Below is a quote from post #20.

"Jay is 100% correct about Speedmaster struts. The bushing slides into the 1/4" stuffing tube the goes into the strut, if you run it that way. Also note that the distance between the drive dog and strut has to be less than the width of the collar on the flanged Speedmaster bushing. Otherwise it can come out of the strut and cause issue(found out the hard way )."

This is telling me I should use a bushing that has a collar with at least a 5mm width. Is anything like this available? Any thoughts on the subject?

[tlandauer]

Interesting thread you dug up. Wish I had read it sometime ago. I am more confused now however: let's talk about the gap : the purpose is to allow shrinkage of the cable under load. That means a gap between the drive dog to ANY surface that is fixed, not moveable. The bushing will slide in and out a bit, assuming it is "in" all the way, you measure the gap between the drive dog and the back of the flange( collar) , the width of the flange/collar doesn't matter. When and if the bushing is at the "out" position, it is not in a fixed position so if under extreme case the cable would require that much shrinkage, it will simply push the bushing back---I doubt this will happen under a stock set up.
Bottom line for me is that when I lube everything and re-installing the cable, I push the busing all the way in and then measure the gap. The width of the flange/collar doesn't concern me that much.
And I could be totally wrong in my thinking and should start all over again?

[4mulafastech]

Thanks tlandauer. Yes, I always set the drive dog gap distance from the strut. I slide the bushing all the way into the strut (it actually goes in beyond flush, or slightly recessed). The manual states 4-5mm gap, and that is with a stock set-up, so I assume that much is needed(?).

The bushing slides easily in-and-out of the strut. Running my stock flex shaft I never saw the bushing out of the strut after running. Just yesterday I ran with the upgraded shaft and stock bushing and I noticed a drop in speed. After bringing it in I saw the bushing all the way out and against the drive dog. I actually think once the bushing collar is out of the strut the prop torque will push the shaft off center and the edge of the collar will prevent the bushing from inserting back into the strut. This may explain the drop in performance (added friction). The motor was definitely down in rpm and was hotter after the run.

I'm no expert by any means on FE boats, but I really would like to understand and incorporate the best solution. I believe there are several experts on this forum, even the designer of the Revolt 30. I'm hoping some will chime in.

[4mulafastech]

One other bit of information. I put the the stock flex cable back in and the performance was definitely back! I kept an eye on the bushing and noticed it was always in the strut after the run. Btw, I use the blue Grim Racer grease on a regular basis. Thanks.

[TheShaughnessy]

Can you take another pic with the bushing pressed all the way in. From the pic posted it looks like you don't have enough gap, causing the flex to rub against the strut and that would cause a decrease in speed and higher motor temps.

[tlandauer]

I understand now, your situation is different than my SpeedMaster strut where the collar can't be pushed in all the way to flush or recess position.

Sent from my Droid using Tapatalk 2

[4mulafastech]

TheShaughnessy, here are a few pics. This is with the drive dog at the minimum recommended clearance of 4mm. With the bushing all the way back the 3mm wide collar is out of the strut. When I start my runs the bushing is all the way in the strut. In this pic it is shown about flush, but the bushing will actually go in a bit further, like 1-2mm. I have not seen any indication that the drive dog is making contact with the strut at this gap. Thanks.

I cleaned the grease off the parts for pics.

pic1.jpgpic2.jpgbushing.jpg[

[TheShaughnessy]

Pretty strange. So all you did is change the flex and now it runs slower and hotter?

[martin]

When you upgraded the flex did you go from the .150" flex up to .187" flex, on some boats with short stuffing tubes with more accute bend in the tube you can get more friction with the thicker .187" flex not liking the bend the tube has.

[martin]

As long as the bushing is free to float & no binding it matters not whether the bushing is forward in the strut or out against the dog as long as the gap you set is sufficient.

[4mulafastech]

TheShaughnessy, yes, that is correct. I only ran two times with the new shaft and the only common thing that I noticed was the bushing was out of the strut on both occasions and it ran slower and hotter.

[martin]

Did you mean the flex is .187".

[4mulafastech]

When you upgraded the flex did you go from the .150" flex up to .187" flex, on some boats with short stuffing tubes with more accute bend in the tube you can get more friction with the thicker .187" flex not liking the bend the tube has.

martin, the upgrade flex is .150" OSE (ose-revolt-cable). It got me thinking and below is a picture showing the stock flex (top) and the OSE flex (bottom). The solid part of the shaft is .50" shorter. As a reference I positioned the bushing about in the position it would be as installed. The flex part of the cable is fairly deep into the bushing and I wonder if that could have an effect with pushing the bushing back(?)...

cables.jpg

[4mulafastech]

As long as the bushing is free to float & no binding it matters not whether the bushing is forward in the strut or out against the dog as long as the gap you set is sufficient.

The bushing is free to float, but when it is back against the drive dog the bushing collar is out of the strut. When the back, or collar, of the bushing is out of the strut, the prop shaft has no radial support back there and you can physically wobble it around. It's hard to say exactly what it is doing running at high rpm in the water, but my thinking is it can't be good.