Prop Shaft Runout - Help Needed

[King295]

Looking to RDP for some help. Before we dive into things, let's start with the back story(ies) that led me to needing some help.

Incident #1 - Seadoo cuts me off going through a narrow stretch of the lower river where I was running in the deep line. I had to cut to avoid hitting said seadoo and crossed out of the deep line and my prop hit a sand / soft rock bar. Didn't feel the hit very much but heard it loud and clear and kept rolling back to my place. Noticed a slight vibration upon acceleration when I was headed for the launch after dropping everyone off. I decided the prop wasn't worth sending out for repair as it was the original prop (2004) and was an OJ as opposed to the newer Acme props which are CNC'd. All prop blades blades had some fair size knicks / bends.

Response to Incident #1 - Bought a new ACME prop.

Incident #2 - First day with new prop, headed up from Havasu to Topock last month to run the new prop. Had some lunch and headed back down river. Between the gorge and the mouth of the river there was a mass group of kayaks and canoes on the AZ side and a boat was coming up river giving them room. I was hugging the AZ side on my way down since I knew there was a sand bar on the CA side but I underestimated how far out it came (about 1/2 way as it turns out) and I hit the sand bar at about 20-25 mph. The boat drug about 25' feet and came to a stop. A kind group of fishermen and a pontoon helped out and we got it off the sandbar and I limped back to the marina with a severely bruised ego and another damaged prop.

Response to Incident #2 - I sent the new, newly damaged, prop to have it repaired and here was the result:

While the repairs are being done I figured what the hell, I'm going to grab another new prop and use the repaired ACME prop as a spare. Due to hitting rather hard (stopping me in my tracks) in Incident #2 my prop repair shop recommended that I check my prop shaft to ensure I did not damage it. Now I should preface I am by no means a mechanic so I called up my buddy that is a mechanic and he let me borrow his dial indicator with magnetic base. I took two different measurement points. They yielded rather quite different results which is why I'm looking for help/advice here.

Video #1
Here I put the dial indicator just before the prop shaft strut. I noticed there is some play in the cutlass bearing. As far as I am aware this is the original cutlass bearing which is on a 2004 Supra Launch with 700 hours. You can see the dial indicator move pretty drastically when I turn the prop shaft by hand. At the end of this video I push on it from left to right to show the movement.

Here is how I setup the dial indicator for video #1:

Here is video #1:

Here is a picture of the cutlass bearing:

Video #2
Here I put the dial indicator about mid way between the strut and where the prop shaft comes out of the hull. This yielded a much more significant runout than my first video which has me concerned.

Here is how I setup the dial indicator for video #2:

Here is video #2:

What do you guys think based on the above? Am I completely screwing this up and not getting an accurate runout reading? Once again, not a mechanic whatsoever, but I'm out in Parker for the weekend to toy with this and drag it home if necessary. I brought the new prop with me and was thinking I'd toss it on and go test it to see if I have any vibrations. Bad idea?

Any input/advice is greatly appreciated.

 

[lbhsbz]

If I'm seeing that correctly...you've got less than 0.007" in 4+ feet of shaft? It doesn't get much better than that. Run it.

 

[Shlbyntro]

Looks like .010 of run out to me. Not gonna lie, it's not the greatest and I like to see less than .005. If this were an insurance job I'd recommend a new shaft.

That being said I've seen far worse and if you're not experiencing any vibration with your new prop, it's really your call as to it's not bad enough to cause any further damage but may wear out the cutlass bearing on the quicker side. From the picks, your cutlass bearing actually looks to be in decent shape at the moment

What I would be concerned about is: are there any hairline/stress fractures in the gelcoat immediately surrounding the strut. And: is your prop shaft seal still holding a water tight seal when the boat is in the water as they tend to start leaking when experiencing a trauma or in some cases an engine overheat.

If you have the stress fractures or a leaking shaft seal, I'd recommend fixing it all. If all you have is the .010 of run out and all else is ok, then you are in a grey area and it comes down to discretion.

Hope this was helpful.
-Breck

 

[flyingcolors]

check it at the end of the shaft,where the nut goes, do the best you can at the keyway

 

[King295]

Looks like .010 of run out to me. Not gonna lie, it's not the greatest and I like to see less than .005. If this were an insurance job I'd recommend a new shaft.

That being said I've seen far worse and if you're not experiencing any vibration with your new prop, it's really your call as to it's not bad enough to cause any further damage but may wear out the cutlass bearing on the quicker side. From the picks, your cutlass bearing actually looks to be in decent shape at the moment

What I would be concerned about is: are there any hairline/stress fractures in the gelcoat immediately surrounding the strut. And: is your prop shaft seal still holding a water tight seal when the boat is in the water as they tend to start leaking when experiencing a trauma or in some cases an engine overheat.

If you have the stress fractures or a leaking shaft seal, I'd recommend fixing it all. If all you have is the .010 of run out and all else is ok, then you are in a grey area and it comes down to discretion.

Hope this was helpful.
-Breck

In the second video I'm seeing ~.010 of runout as well. From the google searches I've done, which has hits on other manufactureres, .004 seems the recommended peak runout but I haven't been able to determine where that is measured (not sure that it should matter?) nor what it is on my boat which is a Supra Launch 22 SSV.

I have not run a fresh prop on it since Incident #2. I have one here with me and can be on the water in the morning so I think I'm going to give that a run and see what happens. If I have a vibration then I will file an insurance claim and get reimbursed for the prop and get everything done.

I checked around the strut and didn't see any stress cracks but I didn't look THAT hard so I will verify in the morning.

Interestingly enough you brought up the shaft seal. It started dripping every few seconds earlier this season. I tightened it up about 3 trips ago and haven't had an issue since. I will check it tomorrow when I drop it in and see if it has come back. Prior to tightening it up it would puke water when I pulled the plug. Very minimal even after Incident #2 which was a decent run after the hit so I think I'll be good here but either way its getting a new shaft seal this spring. Thinking of going to the dripless deal. What are you thoughts on those?

Really appreciate your input Breck,
Brad

 

[28Eliminator]

.005 to .007 is nothing... I would say the shaft is fine.

Bearing might be shot [emoji6]


Sent from my iPhone using Tapatalk

 

[King295]

check it at the end of the shaft,where the nut goes, do the best you can at the keyway

The keyway runs all the way to the end of the shaft so this isn't a viable option (unless I'm missing something, which is always possible).

 

[BassLakeCruiser]

Turn the shaft at the prop end of it in video #2. Your hand is likely doing most of that movement. Put a fresh strut bearing/bushing in it if it hasn’t been changed In a while and try it again. I’d say those soft props aren’t going to let you feel that deflection in a comp ski boat anyway

 

[Wheeler]

I would get a different style indicator to start with.

 

[Shlbyntro]

In the second video I'm seeing ~.010 of runout as well. From the google searches I've done, which has hits on other manufactureres, .004 seems the recommended peak runout but I haven't been able to determine where that is measured (not sure that it should matter?) nor what it is on my boat which is a Supra Launch 22 SSV.

I have not run a fresh prop on it since Incident #2. I have one here with me and can be on the water in the morning so I think I'm going to give that a run and see what happens. If I have a vibration then I will file an insurance claim and get reimbursed for the prop and get everything done.

I checked around the strut and didn't see any stress cracks but I didn't look THAT hard so I will verify in the morning.

Interestingly enough you brought up the shaft seal. It started dripping every few seconds earlier this season. I tightened it up about 3 trips ago and haven't had an issue since. I will check it tomorrow when I drop it in and see if it has come back. Prior to tightening it up it would puke water when I pulled the plug. Very minimal even after Incident #2 which was a decent run after the hit so I think I'll be good here but either way its getting a new shaft seal this spring. Thinking of going to the dripless deal. What are you thoughts on those?

Really appreciate your input Breck,
Brad

Run out is measured as a maximum at any location on the shaft, usually near center like where you were measuring.

As far as dripless packing, I'm not a huge fan as they seam to be sensitive to ground strikes and engine overheats (they rely on cooling water being pumped to them by the engines raw water pump) and once they start leaking, you generally cant get them to stop and then you have to pull the shaft to replace them. I prefer a traditional style packing gland with GFC packing. Its graphite based packing material instead of the traditional waxed rope and you tighten it right to the point where it quits dripping. (As opposed to traditional packing that wants a slow leak) it effectively accomplishes the dripless desire and is also still serviceable. Best of both worlds.

 

[oldschool]

Pull the propshaft and have it checked. While it’s out replace the strut bushing(easy) and the prop shaft seal(easy too). If your boat has that many hours those two parts need to be replaced. Especially if you can grab the prop shaft and move it back and forth. You can use a brass/rubber or fiber bushing in the strut.

 

[Carlson-jet]

Grab the shaft and jerk it around. Jokes end here<<.
Deduct that from the runout.
I know nothing about V-drives, but that amount of runout could cause considerable vibration on machinery I'm used to working with.
I'm also a little apprehensive about the distance between the magnetic mount and the tip of of the indicator. I would be more comfortable with the indicator clamped to the strut for a more accurate reading.
I guess it depends on the RPM's the shaft will be turning and what the clearance is on the shaft and bearing.
I know my terminology is not probably correct for V-drive stuff.

 

[King295]

I would get a different style indicator to start with.
View attachment 827087

I'm already working with borrowed tools that I don't know how to properly use. Why would a differently tool change anything or is this one of those try a new prop deals?

Run out is measured as a maximum at any location on the shaft, usually near center like where you were measuring.

As far as dripless packing, I'm not a huge fan as they seam to be sensitive to ground strikes and engine overheats (they rely on cooling water being pumped to them by the engines raw water pump) and once they start leaking, you generally cant get them to stop and then you have to pull the shaft to replace them. I prefer a traditional style packing gland with GFC packing. Its graphite based packing material instead of the traditional waxed rope and you tighten it right to the point where it quits dripping. (As opposed to traditional packing that wants a slow leak) it effectively accomplishes the dripless desire and is also still serviceable. Best of both worlds.

Good info, thank you again. I will talk with my boat mechanic this spring and have him do this. Really appreciate the info.

Pull the propshaft and have it checked. While it’s out replace the strut bushing(easy) and the prop shaft seal(easy too). If your boat has that many hours those two parts need to be replaced. Especially if you can grab the prop shaft and move it back and forth. You can use a brass/rubber or fiber bushing in the strut.

I'm going to have it pulled this spring but wanted to see if it was an urgent file an insurance claim kinda thing. I'm not big on insurance claims and I agree at 700 hours its ready for a freshen up.

Grab the shaft and jerk it around. Jokes end here<<.
Deduct that from the runout.
I know nothing about V-drives, but that amount of runout could cause considerable vibration on machinery I'm used to working with.
I'm also a little apprehensive about the distance between the magnetic mount and the tip of of the indicator. I would be more comfortable with the indicator clamped to the strut for a more accurate reading.
I guess it depends on the RPM's the shaft will be turning and what the clearance is on the shaft and bearing.
I know my terminology is not probably correct for V-drive stuff.

LOL! The strut is not magnetic, tried that. The boat rarely sees over 3K so I don't think its that big of an issue but tomorrow's test may say otherwise. Either way I'll be doing some extra maintenance this year.

 

[Carlson-jet]

LOL! The strut is not magnetic, tried that. The boat rarely sees over 3K so I don't think its that big of an issue but tomorrow's test may say otherwise. Either way I'll be doing some extra maintenance this year.

That is why I said Clamped.

 

[SoCalDave]

Like someone had mention earlier I would check runout as close to the end of the prop shaft as possible. With a prop strike that would be the most logical place it would be bent.
Place the indicator within the first .010 of when it makes contact with the shaft that way when you rotate it and the indicator hits the keyway area it will not have a big rebound when getting back on the shaft.
Hope this helps.

 

[supernick]

First video about 4 thou runout at shaft support.
2nd video about 10 thou middle of shaft. Shaft is bent in the middle time for a new one. It’s going to start taking out bearings

 

[King295]

That is why I said Clamped.

I'm a CPA, not a magician.

Like someome had mention earlier I would check runout as close to the end of the prop shaft as possible. With a prop strike the would be the most logical place it would be bent.
Place the indicator within the first .010 of when it makes contact with the shaft that way when you rotate it and the indicator hits the keyway area it will not have a big rebound when getting back on the shaft.
Hope this helps.

That makes sense, thanks for the tip. I'm not that "mechanical" so with a tool called a dial indicator to say I'm winging it would be an understatement. I'm going to toss a new prop on tomorrow and see what happens.

First video about 4 thou runout at shaft support.
2nd video about 10 thou middle of shaft. Shaft is bent in the middle time for a new one. It’s going to start taking out bearings

That was my concern and I think it may be true. If I have any resemblance of a vibration tomorrow I'll be replacing it now. If not, I'm going to have my boat mechanic make the call. Thanks for the input.

 

[buck35]

Since no one else has mentioned.... Stop running aground.
Sorry couldn't help myself. Hope you are good for the weekend!

 

[Wheeler]

I'm already working with borrowed tools that I don't know how to properly use. Why would a differently tool change anything or is this one of those try a new prop deals?

I believe there is too much room for error using a plunger style dial indicator in this application.

 

[King295]

Since no one else has mentioned.... Stop running aground.
Sorry couldn't help myself. Hope you are good for the weekend!

I’m surprised it took this long for this advice, but to be fair I’ve never hit before this year and I’ve spent 20 years on the lower river.

First one was a known risk, second was just dumb on my part. If I can adopt your advice I will never have to use this dial thingy-ma-jigger ever again and I’d be happy about that.

 

[Shlbyntro]

Have you tried a new prop? Oh wait you already answered that didnt you....

 

[RiverDave]

Stop stop stop..


without turning the prop shaft at all if you put it back by the strut, and you just push on it back and forth and up and down how much movement are you getting?

if you are getting a bunch than it isn’t gonna matter what the readings are when you are turning it as it isn’t supported when you are turning it.

Start there and take a video and post it up.

 

[RiverDave]

By the way I don’t know what an acceptable amount of run out is, but .010 isn’t shit across big distances like that.. Add in the fact I think you have some play on both ends of the shaft and it really isn’t much..

I’d be surprised if they are that straight from the factory?

To put this into perspective.. If you have normal hair it’s about .003 thick. If you have thicker hair it’s usually .004-.005 thick. We are talking about literally two to three human hairs across multiple feet? That’s pretty tight for something that isn’t overly precision to begin with.


Anyhow as said above check to see how much play you have in the bearing setups or shaft supports at the end first.

 

[nowski]

I'd start by replacing the strut bushing this alone should decrease the total run-out. Note: The further the indicator reading is from the strut bushing (as seen in video 2) the greater your run-out will be. I'd also be willing to bet that the prop shaft will show signs of wear at the strut bushing location if so replace.

Travel indicator versus test indicator, either will work just the test indicator will be more sensitive. Regardless of what indicator is used the readings should be the same, .010 run-out is .010 run-out.

 

[RiverDave]

I'd start by replacing the strut bushing this alone should decrease the total run-out. Note: The further the indicator reading is from the strut bushing (as seen in video 2) the greater your run-out will be. I'd also be willing to bet that the prop shaft will show signs of wear at the strut bushing location if so replace.

Travel indicator versus test indicator, either will work just the test indicator will be more sensitive. Regardless of what indicator is used the readings should be the same, .010 run-out is .010 run-out.

 

[Carlson-jet]

At the RPM's indicated and to have a good holiday, unless there is considerable vibration, I would have a good weekend/ week and check things afterwards. Merry Christmas.

 

[King295]

Stop stop stop..


without turning the prop shaft at all if you put it back by the strut, and you just push on it back and forth and up and down how much movement are you getting?

if you are getting a bunch than it isn’t gonna matter what the readings are when you are turning it as it isn’t supported when you are turning it.

Start there and take a video and post it up.

See Video #1 starting at 16 seconds. I am not spinning the shaft and just pushing on it to the right. There looks to be about .004 of movement without spinning. There was even less movement when pushing to the left, up or down.

 

[King295]

I'd start by replacing the strut bushing this alone should decrease the total run-out. Note: The further the indicator reading is from the strut bushing (as seen in video 2) the greater your run-out will be. I'd also be willing to bet that the prop shaft will show signs of wear at the strut bushing location if so replace.

Travel indicator versus test indicator, either will work just the test indicator will be more sensitive. Regardless of what indicator is used the readings should be the same, .010 run-out is .010 run-out.

Good info, thanks. I will have the bushing replaced this year for sure and have the shaft inspected in the process. I came out to the river this weekend to make make sure I didn't have a bigger issue from the hit.

 

[King295]

At the RPM's indicated and to have a good holiday, unless there is considerable vibration, I would have a good weekend/ week and check things afterwards. Merry Christmas.

I don't intend to do too much boating this weekend, just checking for vibration. I'm already dreading get wet at all self-launching since this is a quick solo trip.

 

[King295]

Well.... I ran the boat today and it has a slight vibration getting on plane and above 2,000 RPM. I put a message into my mechanic and will be getting it in shortly to figure out what needs replacing.

Thanks everyone for your help here. RDP comes through as always.

 

[King295]

Sent from my iPhone using Tapatalk

 

[wettrthebettr]

Pull the propshaft and have it checked. While it’s out replace the strut bushing(easy) and the prop shaft seal(easy too). If your boat has that many hours those two parts need to be replaced. Especially if you can grab the prop shaft and move it back and forth. You can use a brass/rubber or fiber bushing in the strut.

I AGREE pull the shaft and place it on a V-Block, then check with Dial indicator, replace strut bushing.

 

[RiverDave]

Well.... I ran the boat today and it has a slight vibration getting on plane and above 2,000 RPM. I put a message into my mechanic and will be getting it in shortly to figure out what needs replacing.

Thanks everyone for your help here. RDP comes through as always.

Is thst with a new (untested previously?) prop?

 

[Carlson-jet]

Is thst with a new (untested previously?) prop?

No doubt the prop was not looking good.

 

[HST4ME]

Prop shafts on ski boats usually twist into a wobble. If it had impact damage pull it out and send it to a shop that specializes in I/B shafts.

 

[Carlson-jet]

Tha

Prop shafts on ski boats usually twist into a wobble. If it had impact damage pull it out and send it to a shop that specializes in I/B shafts.

That was awesome. Keith has some talent.
Thanks for link.

 

[King295]

I AGREE pull the shaft and place it on a V-Block, then check with Dial indicator, replace strut bushing.

My plan is to have the entire drive line gone through at this point. Thanks for the info.

Is thst with a new (untested previously?) prop?

Yes it was with a brand new Acme prop.

Prop shafts on ski boats usually twist into a wobble. If it had impact damage pull it out and send it to a shop that specializes in I/B shafts.

Very cool video, I'd be interested to see how he actually straightens it but it looks pretty damn good when completed. A google search of how to straighten a prop shaft showed a bunch of outboard guys either wacking them with a ball peen hammer or using a floor jack

 

[oldschool]

If it’s bent it will get straightened by replacing it. Good idea(like you said) to have it gone through, especially with that amount of hours.

 

[HST4ME]

Very cool video, I'd be interested to see how he actually straightens it but it looks pretty damn good when completed. A google search of how to straighten a prop shaft showed a bunch of outboard guys either wacking them with a ball peen hammer or using a floor jack

Heat. Outboard and s/d shafts can be done the same way. It takes the memory out of the material. There are several shops near me that straighten/polish shafts. Usually I do a dozen or so running gear repairs a season and its half the cost or less vs having new shafts cut.

 

[King295]

Heat. Outboard and s/d shafts can be done the same way. It takes the memory out of the material. There are several shops near me that straighten/polish shafts. Usually I do a dozen or so running gear repairs a season and its half the cost or less vs having new shafts cut.

So all you do heat it up and returns to a true(ish) state? Sounds like you are in the biz (or you hit bottom way more than anyone I have ever head of ) where are you located?

 

[HST4ME]

Michigan. No you just don't heat it up. There is some skill and finesse involved. Its not terribly difficult but experience and patience helps, and the proper fixtures.

 

[King295]

Michigan. No you just don't heat it up. There is some skill and finesse involved. Its not terribly difficult but experience and patience helps, and the proper fixtures.

I'm sure it does require some serious skill. I really admire people that have those skill sets. I learn mechanical things quickly but my bread and butter is on the white collar spectrum side of things. Wish I could wrench on stuff all day and build those skills. I'll be leaving the repair (or replace) to a professional.

 

[RiverDave]

Heat. Outboard and s/d shafts can be done the same way. It takes the memory out of the material. There are several shops near me that straighten/polish shafts. Usually I do a dozen or so running gear repairs a season and its half the cost or less vs having new shafts cut.

If you heat it up does it weaken it?

 

[Shlbyntro]

If you heat it up does it weaken it?

It's like hail damage repair on the roof of a car. Once it takes a bend, the structure of the metal has been altered and it will always have a memory that it will eventually return to. If its causing a vibration, just replace it with a new one and be done with it.

Used prop shafts make great pry bars for prying off exhaust manifolds that have been corroded to the engines. Ask me how I know.

 

[HST4ME]

If you heat it up does it weaken it?

Most outboard and S/D propshafts are spun weld just behind the propshaft seals ,steel behind the seals, stainless in front,stainless and the aquamet material I/B shafts are made of is pretty resilient. Higher HP shafts I dye pen the weld and if there are any fissures, cracks or anything that looks funny into the bin they go.

 

[GRADS]

Wait just a minute. This boat has no outdrive and the boat has less than 500 H.P.???

 

[Shlbyntro]

Wait just a minute. This boat has no outdrive and the boat has less than 500 H.P.???
View attachment 827575

The big block LSX based 454 Ilmors you find in Mastercrafts are making over 500 ponies and they have cats get with the times!

 

[HST4ME]

It's like hail damage repair on the roof of a car. Once it takes a bend, the structure of the metal has been altered and it will always have a memory that it will eventually return to. If its causing a vibration, just replace it with a new one and be done with it.

Used prop shafts make great pry bars for prying off exhaust manifolds that have been corroded to the engines. Ask me how I know.

Rong.

 

[Shlbyntro]

Wrong.

Fixed it for you. Also, I've seen them come back.

My labor to R&R a prop shaft and realign an engine is 4 hours and that's if I'm not dealing with a frozen coupler and I have fair accessibility. And I dont warranty parts or labor on used/refurbed parts. Multiply 4 hours by you local shop rate and ask yourself if it's really worth it to save $110?

 

[wettrthebettr]

I was looking into the cost of a new single taper, 78" long 1" dia shaft and it was going to cost me Price: $352.07 nitrogen strengthened Type 304 stainless steel, Florida to Californy