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.

 

[Water4fire]

Normally when SCer takes a dump. It will not reach but 6000 rpm's/ So check your hoses and go from there. I had a issue with my perfect pass keeping my motors about 500rpms off so I disconnected it. But that was because I want to tune the motors with tiny tach's and make them equal than try to re attach perfect pass. The new SCer's still can have issue's, but not as common. Do you know how to pull and check your SCer?

 

[Rick215HO]

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.

Some thoughts (Rotax 4-TEC package):
imho I doubt is a synchronizer issue because they sync at low speed, the synchronizer is digital on a network (CAN) between dash and ECUs (tough to fail without other error codes). Sounds more like one engine can't keep up with the other under power???

Not having any further clues I would try the following if BRP/dealer does not respond:
Assuming you are mechanically inclined and know how to do it, I think its worth trying something simple... I would try swapping coils and plugs from one engine to another and make sure all coil connections are secure. See if the problem is gone or changes sides.
If you have a software like candoo you can try the cylinder test (turn them off/on individually) and avoid the work...
s,plug torque is 18Nm on the 4-TECs - GAP .75mm

If this problem started after the dealer changed the screen I suggest you try to plug in the old screen temporarily to test.

Good luck! would be interested in knowing what it was when you solve the issue.

 

[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.

 

[dyn4100]

Copied from my other post...2018 Chaparral Vortex 2430 VRX issues:

'Right out of the no-wake zone, the difference in rpm's between the port and starboard was still an issue at speeds above idle. However the motors sounded to be sync'd up. Periodically the Medallion rpm displays would read the same (instantaneous, not a gradual change) with no audible change in rpm. At one point, for diagnostic purposes, I noted a change in 200 rpm on the port reflected a 900 rpm change in the starboard...that difference in rpm between the two should be audible.'

I've driven dual outboard set ups in the past and you can hear if the motors are running at different rpms...I'm assuming this would apply here too. There's an oscillation between the motor noise when the rpm's are different and the oscillation goes away when they are 'sync'd'. The boat's still with the dealership, but given what I'm seeing online, I don't think they're going to find the issue to this particular problem.

 

[juliette]

Update: Our boat is in the shop for the 25 hour service. As for the engine sync issue... the sync module has an adjustable range of 4%. Our RPM difference (when tested by the dealer) was 11% - we had actually seen it higher but nonetheless it was outside of the adjustable range. So, BRP is sending a new module. The issue we had was not related to the Medallion. Yours sounds like a sensor issue.

 

[dyn4100]

Got my boat back from the dealership back in August. RPM differential between the motors is no longer an issue. The tech thought that there were two issues that might have caused the problem but couldn't definitively say which since both issues were addressed before they checked it out on the lake. 1) The port motor was delivered by BRP to Chaparral without catalyst inserts in the housing. 2) The engine cable harness was changed because there was a pushed in power pin to the port ECM. This was actually repaired a few weeks before because the engine was basically turning on/off with vibrations and I wanted to get some hours on the unit till the new harness arrived. I thought this was just a simple harness going to just the port engine but it's a complex harness that actually served both engines with multiple connectors to each motor...maybe had other issues besides the original pushed in pin.
Neither issue inspire confidence in quality control.