Could somebody let me know what controls the opening and closing of the powervalves.

Thanks,

Doug.

On the Yamaha motors it is an electrical control. You can also swap them out to the Sea Doo type gas valves.

Here is some reading that I have found on the operation of power valves in general. Don't know if it will help but some good reading for those that want to learn including myself.

Powervalve breakdown

Rotax Australia

CDI sends a signal to the servo motor which then turns the pulley moves the cable which moves the other pulley which moves the PV arms which move the power valves open or closed

the valves start closed, at around 6200 rpm they open

when the motor is shut off the valves do a normal cleaning cycle and open and close once

[ 08-10-2002: Message edited by: Philip_GPR ]