QSB Throttles Swapped Engines They Control

[alnav]

This is a weird one. QSB 425, Smartcraft, non-DTS setup. On an outing yesterday, there was an initial problem with engine synch with port engine not responding to the master starboard throttle. This resolved and the majority of the trip everything was fine. On the return leg, turned synch off and advanced both throttles to do a WOT check before mooring. Everything was fine (~3000 RPMs) for a couple of minutes then there was a sudden drop of about 1K RPMs on port engine. Initially thought I had picked up a crab pot line. Disabled synch and retarded both throttles to about 1800 RPMs. Checked response on both. No alarms or other temp/pressure anomalies. But, the starboard lever is now controlling the port engine and vice versa. Neither will advance further than ~2000 RPMs). Stopped and checked transmission response at idle. No problems so proceeded with mooring. Restarted engines to see if the problem resolved but no change.
I've been unable to find any internet evidence of this problem. I suspect it is coming from the synch controls but am not familiar with the architecture and what if any modules of the control system to look at. Would be glad to hear thoughts about this problem and suggestions for an approach other than calling in Cummins?

 

[alnav]

This is a weird one. QSB 425, Smartcraft, non-DTS setup. On an outing yesterday, there was an initial problem with engine synch with port engine not responding to the master starboard throttle. This resolved and the majority of the trip everything was fine. On the return leg, turned synch off and advanced both throttles to do a WOT check before mooring. Everything was fine (~3000 RPMs) for a couple of minutes then there was a sudden drop of about 1K RPMs on port engine. Initially thought I had picked up a crab pot line. Disabled synch and retarded both throttles to about 1800 RPMs. Checked response on both. No alarms or other temp/pressure anomalies. But, the starboard lever is now controlling the port engine and vice versa. Neither will advance further than ~2000 RPMs). Stopped and checked transmission response at idle. No problems so proceeded with mooring. Restarted engines to see if the problem resolved but no change.
I've been unable to find any internet evidence of this problem. I suspect it is coming from the synch controls but am not familiar with the architecture and what if any modules of the control system to look at. Would be glad to hear thoughts about this problem and suggestions for an approach other than calling in Cummins?

Some amplification: I performed dockside checks on the behavior this morning. The problem is not as bad as I thought. The starboard lever is controlling the starboard engine and port is controlling port. But, the tachs are actually reversed so starboard engine revs are showing on port and vice versa. Same with the other dash instrumentation except fuel which appears to be from the correct side tanks. VesselView is reading both engines correctly. I didn't test the max RPM so I'm not sure there isn't a problem there. Since the dash gauge is actually Smartcraft data I think the problem must be related to "Easylink" which I believe passes the gauge data through VesselView to the gauges. I've also posted to BoatDiesel to see if there's any help there.