Mechanical fuel pump LOST PRESSURE IN FLIGHT

[soarer20]

Our mechical fuel pump Fuel pump was just replaced as part of the 5 year rubber.

Less than 10 hrs on the new pump. Fuel pressure warning light has been flickering on and off since I got it back from annual.

On take off at about 700 agl I turned off the boost pump, and almost immideatly the fuel pressure warning light went on and the engine started to sputer and lost power. I turned the boost pump back on and the engine started to run normally again.

The mecahnic that did the work thought it was a fuel pulsation issue (SB OSB20-069).

Rotech believes its the pump but can't be sure until we check the entire fuel system.

Has anyone experienced a similar issue?

We want to make sure we properly diagnose the problem but it sure seems to be the pump.

Any thoughts would be helpful!

[Kesk]

What was the outcome? Haven't ever worked on the Rotax Diamonds, so I don't know the system. Certainly sounds like the mechanical pump is the problem.

[Da20Marin]

I'm having a similar issue. Normal run up without the electric fuel pump on. Electric pump on for take off and climb out, level off, switch off the electric pump and I now sometimes get the low fuel pressure warning light on for ~5 seconds before the light turns off again. The A&P took the whole fuel system apart and inspected it, cleaned the sensor, and inspected the inside of the mechanical pump. He could not find an issue.

Here is a link to SB 20-069 which describes the fuel pulsation issue. I'm going to see if we've had this performed this weekend.

If anyone else has ideas before I spend 1k replacing the mechanical fuel pump?

http://support.diamond-air.at/fileadmin ... I-AMMS.pdf