Low RPM Reading for Rotax 912

[Petertanner]

I own a Sportcruiser with a Rotax 912 ULS engine and have recently fitted a D120 in place of the old individual instruments. The system works very well. However the engine RPM display is reading 200 RPM low. The reading is a steady 200 rpm low with no apparent noise or spikes in the display.

During the installation, I connected 1 wire from the engine trigger coil to pin 16 on the EMS and the other trigger wire through a 30k ohm resistor to pin 32 on the EMS.

Can you help?

 

[Dynon]

That sounds right, and dropping just a couple hundred rpms is odd. Doe it do that consistently across the RPM range? What is your pulses/revolution setting? What is your reference for truth? If you're comparing to an old analog instrument, it could be that that instrument wasn't as accurate as the D120 is.