Microlighters

I had a funny experience this morning. Took up a pax - a BEEEEG man. Discovered he was too heavy , did a circuit at full bore for about 10 minutes and said thanks but no thanks - that would have to be it. We taxied to the hangar and I offloaded him.

Then restarted easily and started taxiing back to the holding point. The motor started sounding a bit funny (like an oiled plug),I revved and it was Ok. Then when I let it idle it died and would not start. Tried the choke after a while, it started but when idling died again.

I thought of checking filters, jets, plugs etc. Then decided to try one more time and voila she started and flew for 2 hours with no problems at all .

Could it have been ice in the carbs? I cannot think of anything else. It was cold - 0 celsius on the ground. I am not sure if icing can happen this way.

Maybe the piston even started to cease

If so next time it can block and stop

Overheating will cause that

Full power carb icing, I dont think so.

RH dont be RH, better investigate, or remove cyl. head

Thanks guys

I did not see the temp up high but will rather ceheck to make sure!!

Ja, sound like a 503 problem, and after speaking to someone in the know, about the EXACT same happening to me, he confirmed it. If you have been winding the engine, for a while, and it's hot, let it idle for a few mins, before cutting the engine. he said that if you land, after having been foot heavy for a while, and cut the motor, immidiately after you come to a stop, it's not going to want to start. Here at the coast ( Ballito), It was also due to a bit of card icing, but more-so the hard work. Hope my 1 million Zim Dollars helps!!
Fly right

The good news is that it may have been carb icing or water in the fuel.

The bad news is that one of hte pistons may have a partial siezure, remove the exhaust manifold and intake sockets to inspect the pistons through the ports.

If you find siezure marks on the sides of the piston facing the intake port, that would be a cold siezure, possible due to the low ambient temps.

If siezure marks are visible on the exhaust side, that would be a heat seizure, possibly due to working the engine too hard.

What oil are you using? Mineral or Synthetic?
Is it a 503?
What colour are the plugs burning?

Regards
Niren Chotoki
Aviation Engines & Acc

On Sunday I was practicing emergency landings at Altona, a strip about 10km from FAFK, when we had a real engine out. I had done a 180 degree turning descend from about 500ft AGL with the engine, a 582, idling. I made a hash of the approach and my instructor took control and tried to apply full power and the motor died. We checked the carbs but everything looked fine and the motor started with no problems and ran smoothly. We took off and did about five more power off landings and flew back to FAFK with no further problems. Any idea of what could have caused the problem?

Assuming that there has been no seizures adn that the rigs are seating within specs it could have been as a result of one of 3 possible causes:

1. The carb calibrations are set too rich, or air filters dirty/blocked-when you attempted full throttle from idle the rich mixture flooded the engine causing the failure. The needles and needle jets should be replaced every 150 hours to ensure the correct mixture, if these are worn that will also cause a rich mixture.

2. The prop loaded is too high - the pitch should be set so that your max rpm on take-off should not exceed 6500 rpm

3. During the 180 deg. turn the fuel from the float chamber had run out and when full throttle was opened there was insifficient fuel in the float chamber to deliver the power- also there was not enough time for hte pump to deliver the required fuel to the carb.

Griffin, we had a very similar engine out in Upington at the Bundu Bash a few weeks ago (when applying power after coming off the throttle). I managed to get the motor to die again on the ground by quickly opening full throttle. The only thing we could find was a hair in one of the carb float bowls which was sucked up into one of the jets. Many of the experienced guys I spoke to afterwards said that this would not cause the engine to die, but after removing the hair we could not get it to die again and have flown fine since.

brent:

The only thing we could find was a hair in one of the carb float bowls which was sucked up into one of the jets.

Thats a real hairy story brent
I also cant imagine a hair blocking the jet

Thanks Niren/Demon. Should have said it was very warm and dry. My vote would be 1 or 3.