Always nice to hear your wisdom Bud!
Thanks,
RS
On Sep 5, 2009, at 3:28 PM, "Bud Yerly" <budyerly@msn.com> wrote:
> Bob,
>
> Sorry to hear about your engine woes.
> From my experience in the shop here are some things I've run into:
>
> Check that there is not 912S restrictor in your return line for the
> 914. The restrictor is necessary in the 912S but Rotax forbids it
> in the 914. Make sure the return is not pinched either. See your
> install manual on line with Rotax.
>
> Don't make the mistake of swapping the fuel intake line and return
> lines. (Believe it or not the engine runs, but goofs up the fuel
> metering as one would expect, and won't accelerate properly or hit
> top end.)
>
> I hate to admit that I have seen one fuel pump hooked up backwards
> electrically, and due to plumbing wouldn't feed enough fuel for full
> power, but it would start...
>
> Check your airbox and static pressure sensors aren't clogged or
> kinked, or worse yet still plugged.
>
> The new 914s have the removable fuel pans, and easy access to the
> float bowls. Pull them and check for crap.
> If dirty, get a rebuild kit and clean up the carbs.
>
> Since you have 10 hours on your engine, it may be a mute point by
> now but fuel quality is a combination of the source and materials
> quality in the plane... Fuel lines are not shipped clean and there
> is residue in them as well as the tank. Fuel with ethanol will
> clean better than Av gas.
>
> FBO's do filter their gas to a very high standard, but I find very
> fine white organic material in it that my filters found, so think
> about pre filtering your fuel. Since doing so I've had no problems.
>
> My technique for assuring clean fuel tank and lines:
> First. Get a pre filter funnel for your fuel. Fill the tank to the
> neck with 20 gallons of premium unleaded with ethanol. Shake the
> aircraft and check for leaks.
>
> Next, disconnect the fuel delivery line at the engine fuel regulator
> and pump the fuel back into the cans, alternating between main and
> reserve sides. The filters will clean the tank. The pre tank
> filter funnel will clean the fuel going back in. Fill again, and
> allow to sit. More will settle, so repeat the fuel straining. Then
> I do it one more time (total of three times) to insure tank and more
> importantly the lines are clean. Fuel lines are notorious about
> being dirty. I don't use the filtering gas for my first engine run,
> I Premium gas or Av gas.
>
> While doing the above, do a flow and pressure check. I have a valve
> hooked to the line off the aircraft fuel line with a T and fuel
> pressure gauge to check for fuel delivery pressure and and volume.
> It is also a good time to adjust the fuel flow measuring sensors.
> If you have in and out metering, hook the delivery line to the
> return line and circulate the fuel. Fuel flow should read zero.
> (912S owners can do this with one fuel flow device and the
> restrictor installed and measure the flow rate and pressure delivery
> with fuel returning to the tank.)
>
> Bud Yerly
> Custom Flight Creations
>
>
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