New Bent Driveshaft?

[brapperdoodle]

I really hope I’m doing something wrong here, because it looks to me like my brand new driveshaft is bent. This is a Skat-Trak 144 Set Back Mag, going into a 1995 Yamaha Superjet. Everything is torqued down in the video and I kept having trouble getting my pump aligned. I spun the pump and it looked like my driveshaft has some runout. I marked my driveshaft and using my Cold Fusion alignment tool, it seems my driveshaft is bent. Brand new, been sitting on a shelf for months. How is this possible or am I doing something wrong?

 

[Big Kahuna]

loosen your pump bolts, slide the center section back on. tighten the pump bold back up and then run the same test.

 

[brapperdoodle]

loosen your pump bolts, slide the center section back on. tighten the pump bold back up and then run the same test.

Kind of allowing the center section to “guide” the driveshaft strait? And by center section you mean that keyway for the tool?

 

[Big Kahuna]

Yes.
It does not take much to get that "knock" when you rotate the shaft.

 

[brapperdoodle]

Yes.
It does not take much to get that "knock" when you rotate the shaft.

 

[Big Kahuna]

Well, I was hoping that by putting the shaft sleeve and you loosening the bolts, sliding sleeve in place and then tightening the pump bolts would get you perfectly centered. Where did the shaft come from?

 

[user_error]

Is there any excess material buildup between your wear ring and the pump stator section? If some excess sealant or corrosion existed between these two mating surfaces it would cause a runout issue like you are experiencing.
The absolute best way to test the shaft would be to remove it from the stator section and set it on a some machinist v-blocks with a dial indicator set at multiple points along the shaft.

The factory service manual specifies an acceptable amount of driveshaft runout. I cannot recall off the top of my head but I have seen the values posted on here before directly from the service manual. I would recommend giving the service manual a once-over and measuring the shaft with machinist blocks and dial indicator.

 

[brapperdoodle]

I’ve talked to the supplier and I’m sending it back to get it checked out. I’m just hoping I’m not making some mistake but, to me it seems pretty simple while using that tool... I can’t say that it is 100% a bent driveshaft but something isn’t strait and I don’t feel comfortable pairing up a new midshaft and pump without knowing the driveline is strait. I spent too much time and money to just blow it, I can’t afford to replace any of this stuff, the money has been spent haha. I’m just trying to ride

 

[Harbor]

Yes your shaft tip is bent...

Both my shafts have that issue and have run fine as is... seems holding the shaft by tip with the spline tool and tightening and loosing prop during prop changes or the build bend/stresses the spline tip even more, they come with run out already new. One of mine got worse after a prop change..

What I do is try to split the difference.. bring half the amount that’s out of align to the other side..

On another note, I tried installing that tool to aligned pump then tighten pump But that didn’t work.. also I aligned pump with ski upside down only to find it went out of alignment when I flipped the ski over, ??? That was odd a F.. so had to readjust again..

I’d flip the ski over and align pump best you can while upright and split the run out in half by moving part of it to the other side..

So you’d eye ball it with the cold fusion tool, that lack of gap at 12 o’clock, we want to move 1/2 of that to 6 o’clock.

With ski upright, While re-aligning pump, read the lack of gap all the way around the hole between fixture and the guide that you slide... try to make the amount the same all the way around... also check by feel, the amount you have to push the shaft sideways to get the slide in the fixture, make that the same amount all the way around...

 

[brapperdoodle]

I assumed because it was a brand new driveshaft it would be strait, and the fact they make a tool like that would lead me to believe that it’s possible to get a perfectly strait driveline. I guess nothing is perfect but again, I bought a Skat-Trak Set Back pump so it needed a lengthened driveshaft and I assumed it would be in tolerance being a new driveshaft. I realize the only way to truly know is to remove the shaft and check runout properly with V blocks and a dial indicator. I don’t know if the spec is the same for the longer driveshaft or what a safe amount of runout looks like at the splines when measuring it as I did. Like I said, I’m just trying not to waste money that I don’t have! I’m sure some can relate to this situation. Im just doing the best I can to check and double check my work to do it right the first time

 

[Big Kahuna]

Ok, if lengthened, that may be the cause, would not be hard to get it out of spec when welding.

 

[Roseand]

Yes your shaft tip is bent...

Both my shafts have that issue and have run fine as is... seems holding the shaft by tip with the spline tool and tightening and loosing prop during prop changes or the build bend/stresses the spline tip even more, they come with run out already new. One of mine got worse after a prop change..

What I do is try to split the difference.. bring half the amount that’s out of align to the other side..

On another note, I tried installing that tool to aligned pump then tighten pump But that didn’t work.. also I aligned pump with ski upside down only to find it went out of alignment when I flipped the ski over, ??? That was odd a F.. so had to readjust again..

I’d flip the ski over and align pump best you can while upright and split the run out in half by moving part of it to the other side..

So you’d eye ball it with the cold fusion tool, that lack of gap at 12 o’clock, we want to move 1/2 of that to 6 o’clock.

With ski upright, While re-aligning pump, read the lack of gap all the way around the hole between fixture and the guide that you slide... try to make the amount the same all the way around... also check by feel, the amount you have to push the shaft sideways to get the slide in the fixture, make that the same amount all the way around...

X2, mine isn't perfectly straight either. It is very easy to make that tool hang up!
You can do a test that will give you a ballpark without using a dial indicator/v blocks
Bolt a straightedge to one of the midshaft inserts on the hull. You want the straightedge to be able to sit across the driveshaft. Let it sit against the driveshaft, lightly snug the bolt so turning the driveshaft is enough to move the straightedge and keep it in place. Try it at different degrees multiple times and measure with a feeler gauge so you can give us a ballpark idea of the runout.

 

[brapperdoodle]

X2, mine isn't perfectly straight either. It is very easy to make that tool hang up!
You can do a test that will give you a ballpark without using a dial indicator/v blocks
Bolt a straightedge to one of the midshaft inserts on the hull. You want the straightedge to be able to sit across the driveshaft. Let it sit against the driveshaft, lightly snug the bolt so turning the driveshaft is enough to move the straightedge and keep it in place. Try it at different degrees multiple times and measure with a ************ gauge so you can give us a ballpark idea of the runout.

I think I get what you’re saying, I’ll give this a shot probably tomorrow.

 

[brapperdoodle]

So, I’m going to try the strait edge today and see if I can get an idea of how much runout is at the end of the shaft. I was thinking overnight though, I was under the impression that the lengthened driveshaft was a new piece. A few people have mentioned that they are actually 2 shafts welded together to make a correct length. If that is true, it seems to me it would be near impossible to get it strait and I’m wondering if another “new” driveshaft will be any better/worse or the same. Can anyone shed some light on this? I don’t want to take this apart or send it back if I don’t have to. I’m not familiar with the set back pumps and didn’t realize this was the case.

@Sanoman mentioned to ask @Sasquachcrap any thoughts?

 

[jetfreak78]

So, I’m going to try the strait edge today and see if I can get an idea of how much runout is at the end of the shaft. I was thinking overnight though, I was under the impression that the lengthened driveshaft was a new piece. A few people have mentioned that they are actually 2 shafts welded together to make a correct length. If that is true, it seems to me it would be near impossible to get it strait and I’m wondering if another “new” driveshaft will be any better/worse or the same. Can anyone shed some light on this? I don’t want to take this apart or send it back if I don’t have to. I’m not familiar with the set back pumps and didn’t realize this was the case.

@Sanoman mentioned to ask @Sasquachcrap any thoughts?

New oem shafts are also welded together from 2 pieces... So I think it is possible to do this correct...

 

[Harbor]

Your doing ever thing right & others have complained about run out on new shafts with .120

Shaft wobble is common..,

Like I said mine got worse after a prop change. I had the spline tool in vise and pump supported at the same height as vise. With 2 wrenches on prop Tool I could see the shaft flexing as I tried to get the prop loose...could also see the shaft twisting....

Anyways I recently shipped my Other pump, skat set back with custom length shaft, to a professional for unrelated reasons, pump was built originally by a well known builder/tuner... ive ran this pump for 1 season now.,

So he happened to inspect my pump after shipping and here is what he said... just turning the shaft by hand mind you....

“All spot on, very well packed!
Pump looks good. A tiny wobble in the shaft but nothing out of the ordinary, never known a perfectly straight shaft on a pump that isn’t out the box new.”

Anyways just thought I’d share since I’ve had the same problem as you...

 

[brapperdoodle]

Your doing ever thing right & others have complained about run out on new shafts with .120

Shaft wobble is common..,

Like I said mine got worse after a prop change. I had the spline tool in vise and pump supported at the same height as vise. With 2 wrenches on prop Tool I could see the shaft flexing as I tried to get the prop loose...could also see the shaft twisting....

Anyways I recently shipped my Other pump, skat set back with custom length shaft, to a professional for unrelated reasons, pump was built originally by a well known builder/tuner... ive ran this pump for 1 season now.,

So he happened to inspect my pump after shipping and here is what he said... just turning the shaft by hand mind you....

“All spot on, very well packed!
Pump looks good. A tiny wobble in the shaft but nothing out of the ordinary, never known a perfectly straight shaft on a pump that isn’t out the box new.”

Anyways just thought I’d share since I’ve had the same problem as you...

Thanks a bunch! Very informative. I’ve had someone else mention that they have seen and run a shaft like that and not had any issues. My main concern here is knowing that this isn’t going to destroy my pump or midshaft after running it. I know it’s impossible to predict the future so nobody could say. I’m just trying to understand why they make a tool to align your driveshaft, if some driveshafts aren’t strait? This is a tough situation for me cause I’ve got a lot on the line.

 

[Harbor]

Thanks a bunch! Very informative. I’ve had someone else mention that they have seen and run a shaft like that and not had any issues. My main concern here is knowing that this isn’t going to destroy my pump or midshaft after running it. I know it’s impossible to predict the future so nobody could say. I’m just trying to understand why they make a tool to align your driveshaft, if some driveshafts aren’t strait? This is a tough situation for me cause I’ve got a lot on the line.

Gotcha. Yeah it will be fine. I’ve ran one for over 4 years and this latest one got a season and is back in ski for this season., no driveshaft Spline Wear or mid shaft spline wear, no mid shaft housing wear either.

My suggestion is flip your ski over and re-align like I mentioned earlier...

But yeah not all shaft have run out as much as others, some are less and some are more..

But the tool to align is still good, as it aligns the shaft to the center of the mid shaft housing bolts instead of the driveshaft tube which my not be on center... it also Helps you find center when you have run out as you can use the tool as a competitor like mentioned earlier...

Good work

 

[brapperdoodle]

Just tried the strait edge method, I’m finding about .80mm of runout at the splines.

 

[hornedogg79]

When I bought my skat 144 setback it came assembled all brand new. The shaft was about crooked as yours. I could see where they welded it together right next to the seal surface on the spline end. I made it wobble as close to the center as possible and moved on. I replaced pump bearings twice over a period of 5 years then stripped the shaft splines 4 years ago. The replacement driveshaft came from the same vendor but looks much cleaner on the spline end and I can't tell if it's been welded. It aligned perfectly in all positions and I haven't had a single issue since.

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