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Pull Throttle to near Idle = Sputter

V

vanboy_hou

I'm New Here
I'll try to describe this....on and O360-A1A w/Ellison TB
Doesn't always happen, but sometimes when coming in to land, I pull the throttle back to near idle (in pattern somewhere for example) and I get an intermittent sputter. Kind of sounds like a faint "pop, pop". Some times its once or twice other times it'll put a string of them together. Sounds like it's coming from the exhaust, but can't tell.

No power loss whatsoever, no RPM change, no hesitation when putting throttle back in and never happens on the ground.

Anybody have an idea what it might be?

Regards,
William
 
Welcome to VAF!!!!

William, welcome, or should that be, Welcome William???

Good to see another new member here at VAF.

What exhaust do you have, I seem to remember this is a characteristic of a four pipe system.

Pretty sure others with more knowledge will chime in on this.
 
This is very common with the O-360 in the RV's with standard exhaust - if you pull the power all the way back on downwind, you get some after-firing popping. It is commonly attributed to unburned fuel in the exhaust system. No apparent harm is done, and if you want to eliminate the noise, don't pull the power all the way off - at least not too quickly.

After awhile, you can use the popping sound to identify RV's in the pattern....:)

Paul
 
Just another thought.
I'm on my 3rd Ellison equipped Lycoming, the idle mixture might be a little rich. Check the manual but you shouldn't have more than a 50 rpm rise using the mixture on shotdown as I recall.
Mike
 
Seminole after-fires too

The Piper Seminole does that too, but from both sides. It has the (L)O-360-AH6A though. I normally heard it when pulling the power off before the flare, or before doing a stall. With a bit of practice, I stopped hearing it. It can hurt the muffler though, blowing out baffles. The exhaust system isn't designed for combustion :D
 
Thank you for the welcome Mike and the quick responses of everybody. This forum is awesome.

I'm glad to hear it doesn't sound serious. It is a 4-pipe. I had thought about adjusting the TB, just not sure so now I will try dialing back the rpm rise and pulling the throttle a little slower and let you know. Thanks guys. --William
 
I never go to full rich for patterns/landing (Cozy IV, O-360 w/Ellison). Full rich seems to be just too rich. I usually approach the airfield leaned out pretty good and richen to something like a peak-power setting for landing. 'Course, if I have to go full throttle, I go to full rich first.
 
Backfiring At Idle In The Air

RV7, TMX IO-360, Dual P-Mags, Silverhawk Injection, MT prop, we have about 5 hours on a new engine.

From the first flight, if I am at a reasonable speed and slowly close the throttle, as it gets to fully closed we are experiencing quite bad backfiring.

Don't usually close the throttle until on short final but am wondering what is causing it and how to remedy.

I am wondering rich idle mixture perhaps ?

Suggestions welcomed - probably won't do anything for a few more hours but when the snow stops we intend to get the flying done........ :cool:
 
RV7, TMX IO-360, Dual P-Mags, Silverhawk Injection, MT prop, we have about 5 hours on a new engine.

From the first flight, if I am at a reasonable speed and slowly close the throttle, as it gets to fully closed we are experiencing quite bad backfiring.

Don't usually close the throttle until on short final but am wondering what is causing it and how to remedy.

I am wondering rich idle mixture perhaps ?

Suggestions welcomed - probably won't do anything for a few more hours but when the snow stops we intend to get the flying done........
Click to expand...

Do not go full rich in the circuit, if you need to go around, remember this........ RED knob, BLUE knob, BLACK knob.

Full rich at take off and lean as you climb, on descent only richen up a fraction IF you need to stop rough running and only just enough, your engine and wallet will love you for it. The old wives tales are just that.........
 
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