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Momentary black smoke


Peter Sheehy
 

Good evening all. I have an X’Air Hawk with a Jabiru 2200A hydraulic lifter engine. I assembled this machine in 2009 and it has performed well for350+ hours. During lockoff, lockout or whatever it’s called -it has been regularly turned over. I did a maintenance flight of over an hour during February which was uneventful. Yesterday, on the second flight of the day, on climb out, she spluttered and vibrated for a few seconds. Observers on the ground noticed a plume of black smoke from the exhaust until I levelled off after the climb. T’s and P’s were normal.  The engine was warm from the previous flight. The choke was not used and was off. I had new fuel and took a Curtis valve sample (clean) prior to flight.
 After a pleasant, smooth I thirty minute flight I put the aircraft back in its hangar at Daedalus (now called Solent airport)- and went home, 75 miles away!
I’m planning to go back soon and whip the carb’ off to check out a possible rich mixture problem. I have been advised to conduct leak down and cylinder compression checks too.
Does anyone else have experience of this fault - or ideas on where to look?
Kind regards, Peter


John Miller
 

Peter:

Everything I have read on inactive engines says just starting them up and running for a brief interval is not the best method for keeping it up to par. A half hour flight with full power take of and cruise time is supposed to good for getting any accumulated oil out of the oil.

There is a possibility that that your float valve temporarily got stuck in the open position causing the bowl to fill and engine to run rich.

Just my guestamation of the cause.

John M


Kerwyn Stoll
 

Hi Peter,
 My 2200 in Skyranger has done that for many years, but only a couple of times a year.. It does it at wide open throttle, when oats are low. My number four cylinder, which is closest to the carburetor, is typically running at an EGT of less than 1100 F (when it happens). I’ve never had anybody mention black smoke. As a remedy, I always Keep my EGTs avove 1100 f (590 C) with my hackman type device. It certainly isn’t a good feeling when it happens, but it is nice to have a way to stop it (mixture control).
I know it could be other things too, but I thought I’d share my experience in case it hrlps. It is awesome having a Heckman device. I wouldn’t want to fly without one.
Best Regards,
Kerdog




On Saturday, April 3, 2021, 2:54 AM, Peter Sheehy <peterjsheehy@...> wrote:

Good evening all. I have an X’Air Hawk with a Jabiru 2200A hydraulic lifter engine. I assembled this machine in 2009 and it has performed well for350+ hours. During lockoff, lockout or whatever it’s called -it has been regularly turned over. I did a maintenance flight of over an hour during February which was uneventful. Yesterday, on the second flight of the day, on climb out, she spluttered and vibrated for a few seconds. Observers on the ground noticed a plume of black smoke from the exhaust until I levelled off after the climb. T’s and P’s were normal.  The engine was warm from the previous flight. The choke was not used and was off. I had new fuel and took a Curtis valve sample (clean) prior to flight.
 After a pleasant, smooth I thirty minute flight I put the aircraft back in its hangar at Daedalus (now called Solent airport)- and went home, 75 miles away!
I’m planning to go back soon and whip the carb’ off to check out a possible rich mixture problem. I have been advised to conduct leak down and cylinder compression checks too.
Does anyone else have experience of this fault - or ideas on where to look?
Kind regards, Peter