fbpx
Login

 

Jump to Forum..

RPM drop with a 914 above 100%

in 912 / 914 Technical Questions 12 years ago

  • Re: RPM drop with a 914 above 100%

    by » 11 years ago

    Sounds like you may still have a fuel delivery issue.

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

      
    Report

  • Re: RPM drop with a 914 above 100%

    by » 11 years ago

    May be the float bowls gasket is allowing boost pressure to escape? Even if you have no fuel stains around the bowl it can happen. Make sure the bowl is not distorted by over-torquing the bolt and the sealing surface is true. Pre-soaking the gasket helps (thanks to Lockwood for that tip)
    Thank you said by: Carlos Chazarra
      
    Report

  • Re: RPM drop with a 914 above 100%

    by » 11 years ago

    Karl, fuelflow is checked as you say, and it is ok. Thanks for the tip.
    Rob,....., I saw right crab tray with some kind of leak of fuel, seen some small drop of fuel coming out from the gasket..... And couple of flights ago, some brown colour ( As from fuel) in the other side of that carb, facing to crankshaft.
    Check that and replaced for new, and say to you.!
      
    Report

  • Re: RPM drop with a 914 above 100%

    by » 11 years ago

    Today I carried out, again, full power tests, once I have checked and cleaned all fuel pipes, distributor, pipes to carbs, carb bowls, floats, jets, pins, and ....still exactly same problem: no more than 4500 rpm and drop to 4000.
    I have checked, one more time, in that position, the level of fuel inside bowls, more precisely, and the difference between left and right is surprising: 40 cc left, 19 cc right.
    I observe as well a slight leak of fuel from rear part of the right carb, probably coming from the gasket, not much, but is dry in the other carb.
    It, then, seems to be fuel delivery issue, as Roger says, in the right carb, with possibly a lost of boost or fuel in it, (as Rob tells).

    Is possible that, if this is the matter, it causes so much drop in t he powerful of a Rotax 914 from 5.500 to 4000 rpm.??
    Anybody have seen a case like this?

    I will have the carbs overhauled, I think.

    Thanks
      
    Report

  • Re: RPM drop with a 914 above 100%

    by » 11 years ago

    Hi Carlos,

    A good carb cleaning and rebuild may be a good idea. I sure hope we aren't missing something simple.

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

      
    Report
You do not have permissions to reply to this topic.
Related Topics
Title Category Replies
914 Return Line and Header Tank 912 / 914 Technical Questions 5
914 Low Power on Takeoff Attempt 912 / 914 Technical Questions 43
Idle RPM Variation 915iS Technical Questions 1
914 Turbo Induction/Air Intake Hose 912 / 914 Technical Questions 1
Oil pressure drops with increasing RPM, but still stays well into the green 912 / 914 Technical Questions 10
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