From the Simjet website. [link=http://www.simjet.com/service.htm]http://www.simjet.com/service.htm[/link]

RPM sensor pick up, some customers have informs us the they in on out of 5 or more starts have aborted starts just after propane ignition or in most cases under 25000 rpm , we found that is due to a week or distorted pickup, this can easily be fixed by neutralizing the pickup with a magnet, remove the front cover with the starter on by taking the 4 pc 2 mm screws of , then take the 2 pc 3mm of the sensor board flip it over to one side and slide a magnet as close as possible over the pickup form side to side a minimum of 6 times like on the picture. this procedure will cure the problem and the output signal will raise 4 times ( this do not have to be repeated later )