SCARAB 195 HOI goes at 10 MPH maximum speed for 7000 rpm and vibrate.

[Thierry]

Hello jet boaters,

I just join this community and I have seen SCARABMIKE is the specialist about JET BOATS and the SCARAB here. What a great knowledge !

We just put in the water a brand new 195 HOI and we are having a problem on this boat.

After one hour of testing under the break-in period recommandation, the boat suddenly start to vibrate at the stern and we lost the possibility to speed it up over 10 mph.
I took it out the water, check under if something was caught in the impeller or the nozzle and found nothing at all. We put back the boat in the water today and same phenomenon occur.
The engine goes up in RPM (6/7000) but we ride at 10 mph maximum only for those 7000 RPM !. If I want to go over 10 MPH, the boat is vibrating and it doesn't want to go.

No error message being seen on the gauges.

Any idea of what't going on ? Did we caught something and the impeller blades could be bent ?

One more question. I have read that a beep should come off when you put the switch clip (lanyard) on the stop switch right before you start the engine to let you know it's on. Am I wrong on this as we have no beep to come off at all.

Thank you in advance for your return.

Very bad impression to start !

Best regards.

Thierry.

 

[swatski]

@Thierry - I am no expert on Scarab, just wanted to give you a quick response. It does sounds like you have something stuck in your pump. You may try the "reverse trick" but I wouldn't overdo it to avoid potential damage to the impeller and wear ring. You may need to get under the boat to inspect and possibly clear the jet through the intake.
https://jetboaters.net/faq/i-keep-getting-stuff-stuck-in-the-pumps-any-tips-to-help-aka-the-reverse-trick.66/
You can use "@" sign to tag members of this forum, such as @ScarabMike.
Cheers,
And welcome to the club!

 

[Speedling]

Certainly sounds like you got a stick stuck in there!
Gotta reach in somehow and un wedge it.
Either it is too big to pass and just spinning, or something wedged in between impeller and pump wall.
Shine a flashlight in there from both sides to check out what you can.

 

[itsdgm]

Yep. I agree with the others. That vibration is cavitation. Just to be sure, during the break in did the boat get up on plane ok? If so, you probably sucked up something. Could be a piece of wood or fishing line (as tiny as a toothpick). If you have t had the boat up on plane yet since new. It's possible that there's sealant missing during the pump install. Scarab had a few issues a while back with this. either way, it should be a simple fix, keep us posted.

 

[rkluck]

Agreed and it can be real small. I have had small sticks and fishing line cause this. Assuming as asked above, that you had run the boat up on plane with no problems earlier it is probably something small.

 

[ScarabMike]

It sounds like you have a breach in the seal, and are cavitating. This was an issue with the early boats. I would check the seal between the engine/pump, and hull. Here are some threads to get an idea.

https://jetboaters.net/threads/scarab-195-rotax-cavitation-problems-plus-other-problems.6647/#post-114178

 

[Thierry]

Hi Guy's,

Thank you all for your comments and your knowledge. No secret for you guy's about jet boats !

I finally stretched my eyes open much better than I did previously while underneath the boat and I saw a little tiny piece of wood which is stashed and squeezed between the edge of one impeller blade and the wear ring.

I believe this is my whole problem here for cavitation, high RPM but no speed.

By the way is possible that something as been damage like a bearing, sealing ring or something else while having 7000 RPM and a jammed impeller (and shaft) not spinning at all in forward or in reverse ? Is there like a "security virtual and automatic neutral" in those cases ? Should I check something in particular or it should be ok ? Is there a bend impeller blade possibility ?

I will have to get some long handle players. This little thing is really clogged and it doesn't want to come out just by moving it one way or the other... To bad we can't spin the impeller backwards...

One more thing. Your forum is very good with a lot of helpful and passionate peoples. I'm a French guy leaving in Tahiti and I will be hanging on in your forum for sure.

Many thanks for your reply on above comments.

 

[swatski]

Hi Guy's,

Thank you all for your comments and your knowledge. No secret for you guy's about jet boats !

I finally stretched my eyes open much better than I did previously while underneath the boat and I saw a little tiny piece of wood which is stashed and squeezed between the edge of one impeller blade and the wear ring.

I believe this is my whole problem here for cavitation, high RPM but no speed.

By the way is possible that something as been damage like a bearing, sealing ring or something else while having 7000 RPM and a jammed impeller (and shaft) not spinning at all in forward or in reverse ? Is there like a "security virtual and automatic neutral" in those cases ? Should I check something in particular or it should be ok ? Is there a bend impeller blade possibility ?

I will have to get some long handle players. This little thing is really clogged and it doesn't want to come out just by moving it one way or the other... To bad we can't spin the impeller backwards...

One more thing. Your forum is very good with a lot of helpful and passionate peoples. I'm a French guy leaving in Tahiti and I will be hanging on in your forum for sure.

Many thanks for your reply on above comments.

@Thierry Glad you found it! I wouldn't worry about bearings. Sounds like a piece of wood got impelled over there, shouldn't cause any damage to the impeller.
And no, there is no true neutral in these boats. That's something to keep in mind - the only way to stop the impeller is to stop the engine!

--

 

[Thierry]

So how the engine can go up to 6/7000 RPM if the impeller is jammed and can not spin at all and there is no neutral ? How does it works ?

 

[swatski]

So how the engine can go up to 6/7000 RPM if the impeller is jammed and can not spin at all and there is no neutral ? How does it works ?

Oh, your impeller is certainly spinning, I think that piece of wood is just immobilized on the impeller and spins along with it against the wear ring, which causes all the ruckus in your pump. Kind of like if you tried to cut through a piece of wood with a blunt knife and got it stuck half way. I'm just speculating of course, but I think that is the most likely scenario.

 

[Bruce]

Welcome Aboard, please tell us more about Tahiti!

The impeller is spinning but the stick is causing a disturbance in the water flow (cavitation) so the pump is not working efficiently. Once the stick and any other debris are out it should return to normal. It is amazing how small items can cause so much trouble!

 

[rkluck]

Now I know someone in Tahiti! We have been thinking of going there! Is it as beautiful as all the brochures show it? I love the Caribbean and the keys how does it compare to those!

 

[Julian]

I'm a French guy leaving in Tahiti and I will be hanging on in your forum for sure.

Be sure to update your profile to add that you are in Tahiti...the closest we have someone to you is Fiji right now! And of course we would love to see some photos of your boat in those amazing waters!!!! Especially in the middle of winter here in the US!

Hopefully we've isolated your problem and you are all set. Those tiny bits of wood are sometimes more troublesome that a full on branch! Hard to spot but cause all sorts of noise. I expect that once you have it out, all will return to normal!

 

[njmr2fan]

@Thierry Welcome aboard! Hope your problem has been solved. Maybe some one can explain the help feature without actually using it? Im not talented enough, but certainly seems like it would be helpful to such a distant member.

 

[Speedling]

Sure!
If you put @....help without the dots in your message it will tag it lije doing @Speedling
Except it messages those that have signed up for it instead of an individual. These people will then respond quickly to resolve your issues!

 

[swatski]

Now I know someone in Tahiti! We have been thinking of going there! Is it as beautiful as all the brochures show it? I love the Caribbean and the keys how does it compare to those!

What I think about Tahiti, is Gauguin.

 

[Sean Scarab 195]

I just bought a 195 and had almost the same exact problem! I took her out for the 3rd time, and had to bring her in at 2,000 RPMs because I would not get any more power at higher RPMs. My Low Oil Pressure light came on after a while. I am taking the boat in to the dealer this week to get it checked out, and after reading this post, I may need to do a better inspection under the boat.

Here is what I posted:
I just purchased a new 2015 Scarab 195 with the 200 hp motor. I took it out with friends twice, then took my dad out. We were fishing just past the breakwater near Long Beach and San Pedro. We were going about 5 mph for about an hour then started heading back in. The boat started reducing RPMs and speed from 7,000 down to 5 then 4,000 RPM. Then we lost almost all power, even when the engine was revving. At 4-5,000 RPM white smoke was coming out the back, so we crawled back in at 2,000 RPMs and it took almost 2 hours to get back to the boat launch.

When we just got in, the Low Oil Pressure Light came on so we turned off the engine for 5 minutes, then started back up and went in.

I'm taking my boat back to the dealer, as it's obviously under warranty, but I'm pretty concerned that we had this issue at just 5 or 6 hours.

It was quite odd, revving the engine but not getting any more power than when idling.

Has anyone had similar problems? I'll let you know what the dealer says once they check it out this week.

Thanks!