Testing Fuel pressure regulator

Valid question if the hose is OK which I need to test ... but to my understanding it is not a vacuum hose as the hose only leads the 'overpressure' and it shouldn't matter pressure wise if it to free air or to the airbox hence this will not impact anything. Probably relates to safety & environmental issues.

Thx for the alt reference for bosch spare part. I will immediately order one at that cost 😄

Hi David

The small hose on the Rotax regulator is between the regulator and the airbox (MAP) reference pressure.  This is mandatory as fuel pressure varies constantly with the MAP of the engine.  The actual pressure is 2.9 bar +/- a small bit as it is a mechanical regulator so there are always some overshoot or undershoot pressures as you vary throttle positions.  Any leak in that small hose would be very bad.  

The aftermarket part (regulator) will not read exactly the same, this has been tested by others, your call. There is no requirement to change until 5 year. 

Cheers