Bing carb alignment

[Skimmer]

I was the unfortunate recipient of an engine out about a year ago (1st in 15 years) - luckily right above a grass farm! One cylinder quit - the engine was still running on one cylinder but on a 503 this only means it can rotate! Both plugs were heavily fouled in one cylinder - strange since plugs always changed in sets. Checked carbs, replaced plugs and flew back VERY carefully after which I replaced the needle&seats but could not really find any definative reason. No more problems until the morning we were due to leave for Numbi when I saw fuel running out of the balance tube on one carb. On close inspection I noticed one of the float guide rods was slightly bent - carefully straightened it and checked the needle & seat yokes that the floats pick up on as well. The float pins only overlap the yokes by about 2 or 3 mm so the rods and the yokes have to be accurately aligned. I believe my engine out was caused by the float jamming the yoke and the fuel level in the chamber overflowing. The bent rod may have been a casualty of barb bowl removal/replacement when checking for water accumulation. (Engine 12 years old, 500hr, DCDI)

[Morph]

Thanks Skimmer

are you asking or telling?

[Skimmer]

Would be interesting to know if anyone else has had a similar problem.

[Morph]

I have had problems before when on finals my engine died. I landed and stopped on the runway. I tried to restart and nothing. I pushed her off the runway and back to the hangar. I tried to restart and she fired to life. Then I noticed a lot of fuel along the side of the fuse. My one carb had been overflowing. I started up and watched the carbs, nothing, then switched my electric fuel pump on and there you go, fuel pissing out.

I opened the carbs and found the float setting to be incorrect. Sorted this out, the needle and seat resealing properly and solved the problem.

I also have noticed that when guys use a pliers to adjust the little centre tab on the float (the tab that presses against the needle, that they bend the float guide rod. It's very easy to do so be careful

Happy to see the safe landing.

Apart from this 12 years of trouble free flying on a 503. Who says 2-strokes are not reliable?

[Skimmer]

There is something to be said for simplicity. Actually when you see all the little bits of maintenance that are required on our aircraft you wonder how they keep the big iron flying!

[Sam]

We have had a similar situation where on low or very high revs everything is fine, however, when we go to med to high revs, the fuel pisses out of the overflow. Will try the alignment and see what happens. Have tried everything else.