Drive shaft and impeller splines stripped

[Solraider]

Sharing this because I have not heard of this happening on this forum.

Murphy's Law at its finest. We are very careful-cautious with our boat, meaning nothing gets wrapped/into the impeller, no rocks, no ropes, no fishing line etc.. Its a 2018 195 250 HP with 58 hours on it. It can be docked several hours and not a drop of water seeps in. After overcoming the initial quality issues last year that have been covered on this forum we thought we had a problem proof boat.

This past Saturday while boating we were running about 5000 rpm when the boat slowed down and RPMs went up amidst a loud rumbling rattling noise from the pump area, we shut it down immediately. On the boat lift I inspected the intake, fixed shaft, impeller, and wear ring with a small mirror and headlamp. They all looked free of issues like nothing ever happened. So then I thought (based on another members issue with finding a small sliver of wood between the impeller and wear ring) that I might have the same issue. With boat in garage I removed the pump. As soon as the four nuts were loosened on the impeller pump housing the housing tipped ever so slightly down - which it should not because the spline shaft and impeller boot should support the pump more then what I saw happen. I took the pump off and set it aside. The impeller boot stayed on the shaft which is wrong, it is supposed to be threaded into the impeller and slide out with the impeller. The pink arrow on the boot photo points to the threads meant for the impeller.

What was the cause? Based on the mechanics evaluation (and I agree with him) the impeller boot was never installed correctly onto the impeller which allowed water to get into the spline mating area, effecting the grease that was in there etc. Over the winter the water that was in there froze and may have expanded the impeller hub. There is a slight crack on the inside hub in the photo. This all lead to the spline wearing and then slipping inside the impeller.

My dealer is 2-1/2 hours away and that's where the boat is now. I like my dealer, they have been responsive to issues. I don't foresee issues in getting this done in a timely manner. Will see how it goes and how Scarab covers this.

Murphy - we still love the boat.

 

[Scottintexas]

it stinks you're having to deal with this, at least you have a dealer you think you can trust and that they think it's a manufacturing issue,

I've never seen a scarab shaft/impeller before, it's odd to me you impeller slips on the shaft at the intake grate, our yamaha's have a 3ft long shaft with the impeller on the end,

Thank you for the pictures and please keep us updated,


.

 

[Beachbummer]

I had the same issue on the opposite side, the PTO side boot was never greased (I had no clue, boat was used and did not know of this need in my ignorance) Turns out some grease on the PTO boot was very much needed, so it stripped both the PTO and the shaft. Then I was over-greasing the PTO side and the boot burst, so I realized there is no way for the grease to escape..so need to add carefully. Best of Luck getting the boat back in service. The good thing is that this is not a complex repair and the dealer should be aware of how to remove these pieces with ease.

If the dealer is giving you too much grief on labor availability, it's not a terrible job to do, but it's likely $400+ between all the needed parts (Pump needs to be opened and oil o-ring replaced too to remove the impeller) If he gets the parts and can't do it himself, you could go and do it if it buys you a boat this year vs next. Maybe just the threat electrifies them!

Removing the shaft can be challenging if you don't know what you are doing due to the floating ring and c-clip keeping it in place on the inside of the engine. I don't think that system has changed on the last 20 years. Getting the C-clip off requires some force to slide the floating ring back towards the pump. I made a jig with a 2x4 to help me push it with a lever. Look into easy ways to do it, there may be easier ways now.

Hopefully the dealer is great and none of this is needed.

 

[Gym]

Sorry to hear this @Solraider. Your mechanics explanation coupled with your pics makes perfect sense. Do you have any warranty left? I hope Scarab does right by you and fast.

 

[Solraider]

Quick update . . . if Rotax would have supplied the correct parts we would be boating today. First round order of parts the impeller was not correct, ended up being a box with two part labels on it (impeller & ignition) and ended up being an ignition part - delayed two days for impeller to come in. Second round issue comprised of drive shaft spline being smaller then the impeller spline, like most businesses everything is computerized and you can not get a person to talk to. So dealer has to wait till Monday to talk to a their contact person and get the correct parts. Very frustrating for me, I hope this is not the norm at the Rotax dealer support department. If Rotax is an ISO certified operation then this area needs to be reviewed and improved. Maybe Murphy is shipping the parts out.

Dealer is trying their hardest to get this done.

 

[Gym]

I'm telling ya, It's the Russians.

 

[Solraider]

and . . . We’re from the government and we’re here to help.

Picked boat up yesterday and it’s in the boat lift. Will go over it this morning and make sure there are no leaks via carbon seal etc.

Ended up with new drive shaft, impeller and wear ring. Labor, shaft and impeller covered under warranty. Being no fault of mine due to scarab not assembling impeller boot correctly we still had to pay for a new wear ring because it’s considered a wear part - ironically needed new one because of bad assembly at factory. Their logic blows my mind. Bought a second one to have on hand.

A big thank you to our dealer for getting this done in a little over two weeks. I’ll be super satisfied if there is no leaks after sitting in water for several hours.

 

[Beachbummer]

Great you got it back. Crappy move from the dealer to charge you for the wear ring. It's a cheap part too compared to the rest that was replaced. Glad it's all back together!!!

 

[Solraider]

Dealer argued and pleaded the circumstances with scarab but they would not budge from their “wear part” definition and not to cover it under warranty. Scarab/rotax definitely need to review their policies that leave a sour taste with customers where they are in the wrong. $60 some bucks is an inexpensive cost to totally make a customer happy. The 60 is probably 30 their cost.

Like you said we got it back. Will go put on a few hours now and hope for the best.

 

[swatski]

Dealer argued and pleaded the circumstances with scarab but they would not budge from their “wear part” definition and not to cover it under warranty. Scarab/rotax definitely need to review their policies that leave a sour taste with customers where they are in the wrong. $60 some bucks is an inexpensive cost to totally make a customer happy. The 60 is probably 30 their cost.

Like you said we got it back. Will go put on a few hours now and hope for the best.

Sounds like your dealer is an outstanding customer advocate and performer. I would not worry about paying for the wear ring insert as it could be a sticky policy issue, sounds like the whole deal was handled extremely positively for you.

--

 

[Solraider]

Follow up report: Have had time to put several hours on it. Noticed a couple differences right away.
1) Prior to this fix the boat (since day one) would pulse cavitate once or twice when going full throttle from an idling speed. It does not do this now so my thought is that the impeller tube seal that was not installed correctly must have induced some air into the impeller.
2) Previously the max RPMs were in the 7700 to 7900 range, now they are 7900 to just 0ver 8000 and our top MPH is just over 40 versus 37.

Best of all there are no leaks when sitting in the water for several hours. Was a concern of mine when the drive shaft gets replaced and the new one slid into the carbon seals.