912is rpm drop

The first thing to do is connect BUDS and look for faults, specifically, misfires.  But, if I were to troubleshoot the old fashion way…

This could be an injector problem or an ignition problem. However, you are seeing symptoms on both cylinders 1&2 at the same time and it seems unlikely that you would get two failing injectors at the same intermittent time intervals. So I would start with ignition. If you are losing one plug on both cylinders this could account for both the rough running and the high EGTs. With one plug not working the fuel burn is slower so more heat escapes into the exhaust when the exhaust valve opens.  

Double coil pack SP1 handles the bottom spark plugs on both cylinders 1&2, and coil pack SP2 handles the top plugs on those same cylinders. So if either of these coils are failing, or the primary side wire connectors are loose, that would drop one plug on each of cylinders 1&2. However, it’s lane A that’s having the problem, and Coil pack SP1 is controlled by lane A, so start with this coil.

I would check the wiring to the 12V (primary) side of the coil, specifically the 12v spade connectors. The earlier 12V spade connectors are known for getting loose and were recently upgraded by Rotax. You can also check the spark plug wires where they connect to the coils, but it’s unlikely both would be loose, so I’m betting on the 12v spade connectors being loose or a failing coil.  

Thank you. I will start there.

I downloaded the fault codes but they don't mean much to me. someone with more experience probably could see something useful.

Marty

Marty

If you post the BUDS fault log file folks here will help you decode it. Also, I forgot to mention to check the fuses in the Rotax fusebox. Specifically fuse F7 which powers coil SP1, and fuse F9 which powers coil SP2. If a coil goes bad or a loose connector is arcing, that can blow one of these fuses. And take a look at the spark plugs themselves to see if there are indications the bottom or top plugs are not firing.  Typically if these things I mention are a problem you would see a lane fault, but even without that I would still check these items first.

thanks, I will attempt upload the zip file. connections looked good and tight by the way on SP1. 

Marty

I can't seem to upload the file. not sure if it is because I am a new member or not.