fbpx
Login

 

Jump to Forum..

Fuel Pressure alarm

in General Tech Discussion 10 years ago

  • Re: Fuel Pressure alarm

    by » 10 years ago

    Switch off your fuel supply either in flight at cruise power or on the ground at higher rpm and watch the pressure drop; note when the RPMs start to drop off. The engine runs pretty smooth and at a lower fuel psi than you might imagine.
      
    Report

  • Re: Fuel Pressure alarm

    by » 10 years ago

    Where does your drain hose exit or end on the plane or in the cowl? Is it getting any positive pressure from its position?
    Do both of you have a fuel re-circulation line and is your fuel hose in fire sleeve?

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell

      
    Report

  • Re: Fuel Pressure alarm

    by » 10 years ago

    My fuel pump drain line exits at the bottom rear of the cowl, where the airflow thru the cowl exits.
    Yes, I have the fuel recirc line installed per Rotax instructions, and my fuel lines are fire-sleeved (except where they split to go to the two carbs).
    One thing I have wondered about: My carb vent tubes are routed into the back side of each air filter. Could this be affecting my fuel pressure on full power climbout?
      
    Report

  • Re: Fuel Pressure alarm

    by » 10 years ago

    I have almost the identical problem. I replaced an old style pump with the new style and my pressures are very low without the aux electric pump running. (brand new pressure sender)
    From a different thread on the 912/914 forum I found out the it is quite possibly caused by my drain line exiting beneath the cowl.
    In a nut shell, if there is too much pressure (or too little) in the pump drain line, the diaphragm will not make a full stroke. The pressure and volume will drop. I haven't been able to move my drain line into the cowling yet due to weather but I hope to test it out in a day or two.
    No possible way your carb vent tubes can effect fuel pressure. If they did somehow manage to suck enough fuel to lower your pressure, they would be dumping a huge amount of raw fuel into your carbs.
      
    Report

  • Re: Fuel Pressure alarm

    by » 10 years ago

    This is really a very common concern with the newer engines/fuel pumps. There are 3 of us here in the Portland, OR area experiencing the same thing and quite a few more I hear on various forums. It would sure be a load off our minds if someone from Rotax would say its OK to set the lower alarm limit at 1.5 psi or so. When the alarm comes on it tends to spook passengers that may be on board even though the engine keeps running fine.
      
    Report
You do not have permissions to reply to this topic.
Related Topics
Title Category Replies
fuel pump failure General Tech Discussion 4
Blended 100LL/Unleaded Fuel & Oil Change Interval 912iS Technical Questions 2
Fuel pressure rise 912iS Technical Questions 7
Clarification on fuel usage General Tech Discussion 2
Wanted WTB Twin Engine Manifold Pressure Gauge Parts 0
Follow Us

Recent Videos

Safety First!

 

To receive critical-to-safety information on your ROTAX Engine, please subscribe to
ROTAX-OWNER.COM

ROTALK News



ROTALK NEWS Episode 5
Rotax-powered Sling aircraft from The Aircraft Factory, the AVMAP Navigation and engine monitoring system, and the Rotax powered Tucano Experimental and Light-Sport Aircraft.



ROTALK NEWS Episode 4
ROTAX's 915iS-powered Aquila A211 test aircraft, the Scheibe SF-25C Falke (first-ever 912-equipped aircraft!) and ROTAX factory in Gunskirchen, Austria.


ROTALK NEWS Episode 3
Michael Smith's Rotax-Powered Searey Circumnavigation, the amazing Rotax-Powered Lockwood Aircam and Anthony Caere's chimpanzee rescue operations.

Prize Giveaway!


SUBSCRIBE NOW
to automatically enter this years draw!

Login