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912ULS 200 Hours since new: Run up and take off normal. Halfway down the down wind leg, power dialed back suddenly, maybe to half. Didn't feel like a throttle reduction normally does, drop was too quick, like flicking a switch. Tried cycling both mags, no change. Still running smooth, no shaking but would not take full throttle, but I didn't try too hard, just wanted to keep the engine running. Landed non event. On ground, seemed to run ok, would make full rpm, but shook and stumbled when I went from full power to idle on the ground. Question: Does this sound like carb ice, or maybe water in the fuel? Day was abut 45 deg but mostly dry, no visible moisture. Tanks were sumped. Running 100LL but there may have been some auto fuel with methanol in the mix ( switch over for winter flying). High Wing ( RANS S7S) with aux fuel pump, but didn't try turning on pump, was too busy. Engine is kept pre heated constantly at about 80 Deg...

  • Re: Partial Power Loss

    by » 5 years ago


    I've had two partial power losses with my 912uls. Both attributed to debris in the carb bowl. A Small, minute, piece of rubber hose particle, was the problem.

    Once when the engine was new, the other after maintenance. 

    I've heard that jogging the throttle may dislodge a small particle that got sucked up into the jet.

    Flushing  the fuel hoses after cutting can go a long way to prevent this problem.

    Also, finding some black silt in the bowls may be contributed to the use of ethanol fuels. I do not use fuels containing ethanol, ever. 93 octane, non ethanol mo-gas is available in my area.

     

    Rich

     

     

     


  • Re: Partial Power Loss

    by » 5 years ago


    Electric fuel pump should be kept first in mind with partial or full power loss. Also, with the new pump, kept on for take off, climb and landing.

    Rich


  • Re: Partial Power Loss

    by » 5 years ago


    I MADE 3 SEMI EMERGENCY LANDINGS DO TO POWER PARTIALLY LOST. MANY HOURS OF TRIAL AND ERROR BEFORE DISCOVERING THAT THE FUEL TANK VENTS WERE PLUGGED . PUT A SMALL FUNNEL OVER THE FILLER HOLE AND BLOW IN IT WHILE SOMEONE HOLDS THEIR HAND OVER THE WING VENT. WORTH A TRY. 

    RON


  • Re: Partial Power Loss

    by » 5 years ago


    Absolutely use the electric boost pump at a minimum for takeoff and landings.  I leave mine on for the entire flight, I only turn it off to confirm the engine driven pump is operating during my run up and shut down checks. By the way, what is your fuel pressure gauge indication while this power loss occurs?


  • Re: Partial Power Loss

    by » 5 years ago


    I think u did some modifications on your engine for increase of power. If yes then 

    1. Check you airbox solonide valve.i.e Enricher.

    2. Air box temperature max allowed 88C to 95 C.

    3. Electric fuel pump pressure?

     

     


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