2017 255 Cavitation????

[Texas_Transplant]

Good Afternoon, I started having some issues the other evening. Upon acceleration I have was getting massive vibration and loss of power, no issues at idle or really low speed/rpm, no idiots lights on. I assumed I sucked something up so got off the lake found a plastic bag wrapped in the port side. Got it home pulled the pump, pretty easy actually, and got the plastic out (pic attached) and thought I had fixed the issue.



Went back out the next day, same issue, except this time I killed each engine independently to see if I missed something. Lo and behold it was the starboard side that was giving issues. Tore both pumps out again and didn't find anything in either pump. Unfortunately being new to this I am unsure what a bad wear ring looks like. Both port and starboard look about the same to me, starboard has more marks, but cannot even catch a fingernail in the marks and they wipe off in strings. First picture is the port, second is the starboard. When spinning impellers by hand there is a real slight, quick dragging sound at one place, but I can't find anything. Plan to replace both and put my stock impellers back in while I have it all apart.

Does anyone have Amazon links for the impeller tool and rings by chance? Not sure which ones I specifically need.

And any other experienced info would be very helpful.

2017 Scarab 255 Platinum SE with dual NON supercharged motors

 

[Texas_Transplant]

I forgot that I shot a quick video if you turn your volume up and listen closely you will hear the small very very light and insignificant drag on the starboard impeller.

 

[Luc Lafreniere]

Just answered on Facebook, but for the sake of record keeping here.

WR11 if anybody comes across this. That's the tool for the 150HP.

It's a 155mm. Identical parts in the BRP or Sea-Doo part number world.
BRP#0460661.
Sea-Doo#267000419

Just answered on Facebook, WR11 if anybody comes across this. That's the tool for the 150HP.

It's a 155mm. Identical parts in the BRP or Sea-Doo part number world.
BRP#0460661.
Sea-Doo#267000419

So... the 155.5mm, I've seen mentioned in many places. Sometimes it's even labelled 150mm. The official Scarab docs say 155mm. Nothing about a 0.5. But is it possible it's rounded and that other manufacturers don't round? Maybe. I can't confirm that sadly. The BRP and Sea-Doo numbers should be the same part. But if you're buying from Impellers.com, then you have to go based on their descriptions. Make sure you're familiar with the freezer trick to install them. Look it up if you're not.
As for your wear ring conditions, I saw a lot of comments from others. I mean, anything is possible. But what I can tell you is that from that side of the pump, I definitely wouldn't say it's what's causing that vibration. My ring is original at 250h. I have many such scratches and zero issues. I inspect it every year and it's still going strong. I'm assuming the other side of the impellers look just as good?
I'm tempted to say your likely problem was still some sort of debris in there that wasn't clear. I'm having a real hard time believing it's the ring based on that pic. But if the pic isn't showing it well, then yes, it doesn't take much.
It is possible it's something else as mentioned. Drive shaft, bearing, etc. But those are much less likely.

 

[Luc Lafreniere]

And here's my impeller/ring for reference after 250h.

 

[Texas_Transplant]

Well it won't let me upload the video...

 

[Luc Lafreniere]

All good. I will confirm I have seen the video and can hear a slight "ting" when you rotate that impeller and confirm you aren't totally crazy.

 

[jack s]

I have recently had a similar issue with my new 255, found that putting more sealant behind the impeller housing plate and hull really helped on one side anyway! still bad cavitation on the stud side though. Very stuck! people have mentioned about the sir clip holding the carbon seal but a lot of work to get to that

 

[Luc Lafreniere]

I have recently had a similar issue with my new 255, found that putting more sealant behind the impeller housing plate and hull really helped on one side anyway! still bad cavitation on the stud side though. Very stuck! people have mentioned about the sir clip holding the carbon seal but a lot of work to get to that

It's all about making sure the jet pump makes the highest amount of pressure possible. To do that, you need extremely tight tolerances as per the pictures. Beyond that, you also need to ensure the water flows correctly into the intake grate and in the pump with no air bubbles. So things like the impeller boot (rubber thing in front of the impeller) need to be in good shape. Water needs to flow through smoothly in order to not have any cavitation.

Obviously it's quite hard to help you on the internet without a lot more details and pictures.

 

[jack s]

It's all about making sure the jet pump makes the highest amount of pressure possible. To do that, you need extremely tight tolerances as per the pictures. Beyond that, you also need to ensure the water flows correctly into the intake grate and in the pump with no air bubbles. So things like the impeller boot (rubber thing in front of the impeller) need to be in good shape. Water needs to flow through smoothly in order to not have any cavitation.

Obviously it's quite hard to help you on the internet without a lot more details and pictures.

Here are some pictures, the intake grate does have sealant round it but it’s the not knowing how much it’s meant to have as you can see and the gap is where I had to fill in the sealant as there was some missing. The rubber boot is brand new so that’s in good condition. I’d like to get the jets off again and see if the sealant has blown out.

 

[Luc Lafreniere]

I don't think any of this would explain significant cavitation. It's good that any source of potential air bubbles is removed, but I really don't think this is your problem.

Any pics of the jet pump, wear ring, impeller?

Can you describe your observations exactly when driving it? In case this isn't cavitation...

 

[jack s]

I will get some pics of the wear ring and impeller today. But in terms of driving it the port as I said is now fine after the sealing. The stbd there is 1000rpm difference between the 2 engines and it’s like it can’t grip. Sounds like it’s slipping trying to keep a constant speed

 

[jack s]

Took it all apart again today but completely forgot to take pics of wear ring and impeller. It’s all brand new and has the right tolerance between the two so am really stuck now what the issue could be

 

[Luc Lafreniere]

I'll assume you're right of course. Starting to sound like this isn't cavitation, but an engine/drive shaft/other problem.

Is there no dealer or experienced Sea-Doo person near you? This will be very difficult to troubleshoot remotely without someone being able to look, try things, dissassemble or even drive it themselves.

The internet/forum is great when you have specifics, but your symptoms are so broad, it's very hard to give you advice.

 

[FTM3]

Just answered on Facebook, but for the sake of record keeping here.

WR11 if anybody comes across this. That's the tool for the 150HP.

It's a 155mm. Identical parts in the BRP or Sea-Doo part number world.
BRP#0460661.
Sea-Doo#267000419

Just answered on Facebook, WR11 if anybody comes across this. That's the tool for the 150HP.

It's a 155mm. Identical parts in the BRP or Sea-Doo part number world.
BRP#0460661.
Sea-Doo#267000419

So... the 155.5mm, I've seen mentioned in many places. Sometimes it's even labelled 150mm. The official Scarab docs say 155mm. Nothing about a 0.5. But is it possible it's rounded and that other manufacturers don't round? Maybe. I can't confirm that sadly. The BRP and Sea-Doo numbers should be the same part. But if you're buying from Impellers.com, then you have to go based on their descriptions. Make sure you're familiar with the freezer trick to install them. Look it up if you're not.
As for your wear ring conditions, I saw a lot of comments from others. I mean, anything is possible. But what I can tell you is that from that side of the pump, I definitely wouldn't say it's what's causing that vibration. My ring is original at 250h. I have many such scratches and zero issues. I inspect it every year and it's still going strong. I'm assuming the other side of the impellers look just as good?
I'm tempted to say your likely problem was still some sort of debris in there that wasn't clear. I'm having a real hard time believing it's the ring based on that pic. But if the pic isn't showing it well, then yes, it doesn't take much.
It is possible it's something else as mentioned. Drive shaft, bearing, etc. But those are much less likely.

Do you by chance know the seadoo carbon seal kit part number for twin 250

 

[Luc Lafreniere]

I do not. Sorry. I'd just call a Scarab dealer.