912ul woes

[WWhunter]

I had several 'breaks' in my wiring. The way I figured mine out was with the individual 'mag' check. Engine died when flipping the number 1 toggle. Had to wiggle the wires while it was running!!
I then had to pull the braid back to find more. You can easily see the internally broken wire when you bend each individual wire.
My opinion is the wiring harness is borderline quality. I ended up putting tie downs every few inches to stop any further vibrations.
I still have rough running but not nearly as bad as previously.

[bogmonster]

I actually had one ignition finally quit, which got me searching in that area. To finally find it, I was able to do a simple pull test on the wire. I would just grab the wire a couple inches at a time and pull lightly. If it is broken inside, it will stretch. Both sides had breaks.

Another issue I has with vibration a certain rpm was one blade of my warp prop was off 1 degree from the rest.

Good luck finding your gremlin,

Mike

[Av8r3400]

The initial problem with broken wires is not the harness. It's the way they were mounted on the "moving" part of the engine mount exaggerating the vibrations. This will eventually work harden the wires causing them to break.

If you have an early Kitfox with the reversed intake manifolds, it is highly advisable to relocate your ignition boxes to the solid side of the mount. Note the location just "above" the carb in this photo.

[egp8111]

No smoking gun with the test. I pulled the carbs off and shipped them to Lockwood to test on their shop motor. At least that will settle the carb vs. ing.question. Anyone want to place odds?

[Slyfox]

It's because it has a tail wheel. Hay wait a minute, mine has a tail wheel and runs great. forget what I said

[happiestflying]

Have a very similar problem; 912ULS, flip the left ignition module switch (call it "right mag" and lose 300-400 rpm and very rough running. Just started the other day on departure runup; happened to be near the Rotax shop, but after I taxied back he was unable to duplicate the problem; he thought that the only time he'd ever seen such a problem was a cold moist day and that it was carb ice that then melted because I'd warmed the engine. Since at that time both seemed to work fine I flew home.

But, the next time I tried to fly, the next day, same problem came back, and this time did not go away. I've changed all the spark plugs to new plugs (with heat transfer goop applied) on the advice of a number of "mechanics", assuming fouling might have been an issue, but no joy.

Have checked as many ignition module and wiring connections as I could, but hadn't thought that wires could be broken internally. I do indeed have the reversed manifolds and the modules mounted top-dead-center on the engine.

Hope that it's just a wiring break; would hate for it to be a module......will keep y'all posted, and thanks for the advice.

[Planesmaker]

How old is the fuel? Unleaded has a shelf life of only 2-3 weeks. Had a 912 with fuel a few months old, would start and run on choke then stop when choke pushed in. Checked carbs etc then tried fresh fuel, all fixed. Please don't fly with old fuel, one fellow here persevered with flying even though the engine would stop while taxying, the result, broken rings and detonation damage to 1 piston.

[happiestflying]

Just refueled from almost empty tanks on Saturday but have no idea how long it was in the tanks at the FBO. I'm pretty careful about not letting fuel sit too long. Also, I'm using 100LL with Decalin additive.

[Planesmaker]

Happyiestflying I was responding to OP. Sounds like you have a different problem if it is only on one ignition. Check earths and have a close look at the red wire going into the ignition module, common to have the break internally, a light pull on the end of wire may reveal a narrowing of the insulation after it exits the braided section. Hope it is not a module, man they are expensive. Tom

[happiestflying]

Apologies. Will try to keep the thread on track.