Engine that does not turn round full throttle

[Onex107]

One other thing. When I was using 100LL in my low compression Continental, I had a fouled bottom plug every time I flew. I had to run it at 2000 rpm and lean to roughness for a few minutes to clear the plugs and get a good magneto check. The Continental O-200 was designed for 80 octane aviation fuel that had much less lead content and is no longer manufactured. 100LL exhaust pipes are gray inside. Auto fuel pipes are black..

[sonex1374]

Andre,

A few questions:

1) Did you install new spark plugs on your most recent flight test? What do they look like now? Are they black and sooty after just one flight?

2) During the flight test, could you lean the mixture in flight and make the engine run smoother, or did it lose speed, run rough, or quit?

3) What needle do you have installed in the AeroCarb? Which way is the flat side oriented?

4) Have you checked the intake for leaks? A lose clamp could cause problems of all varieties.

I still think your problem may be with the mixture setting. Until you rule this out I would not start replacing ignition components in the hopes of finding and solving the problem. Making a 1/4 turn adjustment to the needle is a large adjustment. It may have been too much. When you say the engine is "struggling to take turns during a fast acceleration", do you mean that even with both ignitions working the engine will not turn up to full rpm? What rpm does the engine make at full throttle? If the engine will no longer reach full rpm at this new needle setting, you are correct that the mixture is improperly set and is too lean.

Achieving a proper mixture setting does not rely on both ignitions operating. First sort out the needle setting, then inspect the magnatrons and other components for problems. I would look at the following things for ignition problems:

1) Does either magnetron show signs of contact along the bottom of the magnetron from rubbing the trigger magnet plate?

2) Have you removed the magnet at any time? It may have been damaged and lost strength.

3) Have you inspected the spark plug wires for signs of chaffing? Are they secured to anything with clamps or cable ties?

Jeff

[Loiret39]

[quote="

1) Did you install new spark plugs on your most recent flight test? What do they look like now? Are they black and sooty after just one flight?
Yes i install new spark plug and they are black after just an hour

2) During the flight test, could you lean the mixture in flight and make the engine run smoother, or did it lose speed, run rough, or quit?
when I try to adjust the mixture in flight, the engine loses turns. it rotates less well

3) What needle do you have installed in the AeroCarb? Which way is the flat side oriented?
Sorry but i dont know the number (I would have to disassemble it to see). I think I have correctly mounted, flat side of the motor side,I would revisit this weekend

4) Have you checked the intake for leaks? A lose clamp could cause problems of all varieties.
I would revisit this weekend

I still think your problem may be with the mixture setting. Until you rule this out I would not start replacing ignition components in the hopes of finding and solving the problem. Making a 1/4 turn adjustment to the needle is a large adjustment. It may have been too much. When you say the engine is "struggling to take turns during a fast acceleration", do you mean that even with both ignitions working the engine will not turn up to full rpm?
the engine reaches full throttle but it coughs and the acceleration is really not straightforward. if the throttle is pushed more gently, then the engine will accelerate normally. it is impossible to fly with such a setting

What rpm does the engine make at full throttle?3200 tr/mn in flight

If the engine will no longer reach full rpm at this new needle setting, you are correct that the mixture is improperly set and is too lean.
the worry is this accélération that is not frank when I depleted my mixture.

Achieving a proper mixture setting does not rely on both ignitions operating. First sort out the needle setting, then inspect the magnatrons and other components for problems. I would look at the following things for ignition problems:

1) Does either magnetron show signs of contact along the bottom of the magnetron from rubbing the trigger magnet plate?
no signs of contact

2) Have you removed the magnet at any time? It may have been damaged and lost strength.
no

3) Have you inspected the spark plug wires for signs of chaffing? Are they secured to anything with clamps or cable ties?
Yes there are some cable attachment for fixing the spark wires so that they do not come to rub on the exhaust pipe

Thanks a lot for your help
André/quote]

[Loiret39]

Hello all,
I found the solution! I bought this second-hand motor and I had to redo it entirely because of large mounting errors.(see here:http://www.achaillous.890m.com/public_html/crbst_77.html)
The only thing I had not touched was the ignition. off after going around for my primary ignition problem, I decided to order and change the magnetrons.
When dismounting the lower magnetron, the cable of one of the candles was protected by an anti-fire sheath. When I removed the cable from the sheath, a piece of hose was threaded on the candle cable about 5 cm. by dragging this piece of hose, I discovered a burn on the cable of the candle of a first assembly too close to the exhaust pipes !!
I think that as soon as the engine took its turns, the tension increased, a priming was done between the cable core and the outer sheath which led to the loss of tower, a cylinder is no longer powered.
After replacing the magnetrons, everything is back in order

[sonex1374]

Andre,

Great news! Protective sheaths, clamps and cable ties over ignition wires have a way of hiding problems. Sometimes these problems are overlooked, because in fact 99% of the ignition wire if just fine. A best practice is to always inspect everything very closely, and never assume anything is OK if you can't actually inspect it. Good work in uncovering the real problem.

Jeff

[Loiret39]

Thanks Jeff,
just a question: is it possible to change the cable of the magnetron or this one is glued on it?

[radfordc]

Thanks Jeff,
just a question: is it possible to change the cable of the magnetron or this one is glued on it?

Yes, it is glued in, but you can change it. Pull out the damaged cable and dig out any remaining insulation. I used solid copper core wires to replace my cable which also was burned through at the exhaust pipe. The wires I used were for Ford tractor ignition, bought on ebay. Any suitable size cable should work.

[sonex1374]

Several people have changed the spark plug wires from magnatron units. Like Charlie says you'll need to dig out the remains from inside the magnatron, but it's not really hard to do. Once it has all been removed, simply insert the new lead and secure with some epoxy, taking care not to get epoxy way down inside the magnatron. It's actually fairly easy to do.

Jeff