Running a Rotax Engine with Pre-Mix Gas: Why Do People Do It?

[Sportster-2001-951C-Stock]

The carbed 951's also have a throttle position switch in the throttle cable that adjusts the timing at 80% throttle. If it is not adjusted correctly you will not hit 6,800 rpm either.

Yes, it's a very noticeable kick at about 80% throttle the MPEM should advance the ignition timing about 10*, a big jump you can feel. At first mine wasn't working so it would only rev to low 6,000 RPM (by my memory), maybe 6,200. It still ran pretty good but FULL RPM was low.

It's easy to test the throttle position switch using a voltmeter to measure the change on one of the MPEM pins, it pulls low the ~5V on the pin to less than ~1V