Twin rotax 200 different rpms under acceleration

[tbauer]

I've got a 2015 Chaparral vortex VRX 223 with twin 200s with approximately 30 hours, purchased new April 2016. I just recently picked up my boat from Plano marine in Longview tx after having some service done. Had the 25 hour service done with an oil change and had the medallion viper 1 screen changed out under warranty due to bubbles in the screen. Now for my problem. My port side motor shows that it accelerates at 2000 rpm less than the starboard side. My starboard motor will accelerate to 7800-8100 very quickly while my port side shows 5500 rpm give or take a few hundred. They only sync rpms at lower speeds and rpms below 5000 rpm never on the top end. This has been an issue since the break in period ended. The dealership said they reset the throttle position sensors and flashed the computers but I'm still having the same problem. Does anyone have any ideas that might help me out? Yes the motor sync is turned on in the viper touch screen. I've visually inspected the intakes and impellers and everything looks fine there. I have two dealerships here in DFW (both Plano marine dealerships) and neither have a technician that has any experience they basically have to call BRP for guidance. Any help is appreciated.

 

[Scott E]

Does the port engine never get over 6000 rpm? If it doesn't it sounds like an issue with the supercharger.

 

[tbauer]

It will go over 6000 rpms but never as fast as the the starboard motor. Not even close to the same speed. Matter of fact it seems like it never reaches 7800-8100 rpm like the starboard side.

 

[blackhawkpilot]

@tbauer - put this in the Rotax Engine Topics discussion page. I think you'll get some more hits from there. Wish I could help. I'm not very engine savvy and have no clue what it could be. https://jetboaters.net/forums/rotax-engine-topics.97/

 

[tbauer]

Sounds good, I will

 

[Scott E]

Check the supercharger hose connections, could be that there is a leak between the supercharger and the intercooler.

 

[tbauer]

Good idea! I'll update this weekend.

 

[Scott E]

Did you figure out your issue?

 

[Jet16]

@tbauer .... I had a similar issue with my 2014 Scarab 215 HO Impulse. Took it to the dealer and they said that they were able to get the engines to about within 500-700 rpms of each other. Was never really happy with this solution, but that was their final answer on the topic. I sold the boat to get in to my Chap, but another theory someone had was that if the wrong type of oil is used or some other chemical brand not specific to the brp engine it could cause an issue with one of the engine sensors thus resulting in the engine sync issue. No idea if this is your problem, but just another theory to ponder. Good Luck!

 

[juliette]

Anyone have any further info on this? We just got our 223 Vortex and have the same problem. Day 1 we noticed this issue. At slow speeds, the engines are about 500rpm apart but at 20 mph, the engines are running at 1000 rpm difference.

Interestingly, at exactly 30mph in ECO mode only, they sync up but otherwise, they don't.

 

[Mr.Happy]

I have the same problem. By slow speed are arround 300-500 rpm different. By full speed to the begin og the year arround 200rpm different (see picture), 3 monath later i have no different rpm, the other problem is i have not the full rpm. Before arround 8000rpm by full speed, now only 7600rpm, get not more by full speed.

 

[Compatico]

@juliette and @Mr.Happy my wife and I were looking at a Vortex on the weekend with the Viper touchscreen and it may have an option for that. Check in the touchscreen System Settings (gear icon)...I believe there is an option to adjust the sync in there? Everything is electronic with the throttle control so it might just need to be reset.

 

[Mr.Happy]

That's not the problem, the problem is, if I have too little RPM, I do not have enough speed . Normally both motors would have to turn 8050 rpm. I did service on the Supercharger, that did not help :-(. Does anyone have an idea what else could be checked?

 

[Mr.Happy]

Here can i see, a short moment maximum RPM, an then i lost arround 400 RPM. What a shit.
20190324_153517_1.mp4