912 excessive RPM drop on lane A

The circling sb did not affect my serial number. I have a guy that has two brand new carbs. He is going to send them to me. I am putting one card at a time on. He seems to think that it might be maybe a plug that has failed in the carb causing a vacuum issue . Can’t hurt to try since he is going to send them to me

Can't wait to hear what you find. You did say something about staying up at night thinking about this. It is an interesting problem.

It will take a couple days to get the new carbs. I’ll keep everyone informed on the progress.Hopefully this will help somebody else out in the future.

While you await the new carbs, replace that ignition switch with a known good ignition switch and see what happens.

You will have to explain to me why you would think my earth toggles are bad. I have two independent toggles for lane A and Lane B. The ignition switch with the key in it only starts the engine and turns on the accessories like panel lighting. You can turn the ignition switch off and the engine will keep Running until you turn the two toggle earth switches off. I learned earth ground from this website LOL. I shut Lane A off and then B off and the engine dies. I would think they are operating properly. If I am wrong please explain. I learn a lot from the expertise on Rotax owners but I only learn because I’m a why guy.