PilotPete
Well-Known Member
- Joined
- Mar 16, 2011
- Messages
- 1,199
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Whatever you want to call it, my IO-540 let out a loud gunshot bang the other day during starting. The engine was warm (taxied over to pumps), and was shut down for 15min or so.
I did a hot start - throttle open slightly, mixture ICO, fuel pump on, ignition on. The prop turned about 5-6 times, and then the engine caught - with a single bang.
Never had this happen before - I've often had problems starting a hot engine after 1/2-hr or so, and usually end up using the flooded engine technique (WOT, ICO). But it has never backfired before.
I've been told by bystanders that they hear the occasional pop during idle taxiing as well, although I don't hear it inside.
I thought the idle pops might be too lean a mixture, either by me, or due to an induction leak, so I checked both sniffle valves for leaks, and ran Mike Busch's induction leak test during flight. Didn't find any problems.
I figure the pop and bang are caused by two different things - one may even be on the intake side, and one on the exhaust side - I don't really know.
Thoughts?
I did a hot start - throttle open slightly, mixture ICO, fuel pump on, ignition on. The prop turned about 5-6 times, and then the engine caught - with a single bang.
Never had this happen before - I've often had problems starting a hot engine after 1/2-hr or so, and usually end up using the flooded engine technique (WOT, ICO). But it has never backfired before.
I've been told by bystanders that they hear the occasional pop during idle taxiing as well, although I don't hear it inside.
I thought the idle pops might be too lean a mixture, either by me, or due to an induction leak, so I checked both sniffle valves for leaks, and ran Mike Busch's induction leak test during flight. Didn't find any problems.
I figure the pop and bang are caused by two different things - one may even be on the intake side, and one on the exhaust side - I don't really know.
Thoughts?
