Did anyone consider that the backfire occured as a result of a loose prop?
Typically the engine pops -then the flyer says uh oh- and when checking, finds that the prop is loose.
Conclusion is that the backfire caused the looseness - not the other way around.
Apparantly there are a shi-load of opinions as to how to best affix aprop but when all is said and done - what matters is clamping tension -it must exceed any rotational loading.
Our two stroke engines rely on an absolutely solidly affixed flywheels - in order to start and run -
I have NEVER had one of my gassers backfire -
had em fire out of phase - with a "whoosh" from the exhaust -.
On the glo engines we all learned to love/hate -the loose prop (single bolt typically) a loose prop always resulted in popping and a failure to start.
( Also, overcompressed 4 strokers were particularly notorious for this .)
On a lawnmower - early type with no indexed blade - these suckers would never start with a slightly loose blade.
Our engine ALWAYS fire just prior to TDC- which results in a sharp kick--if the prop is loose --otherwise -- the flywheel weight of the prop or blade, carries on thru and we get the happy putt-putt noise.
If the ignition is improperly setup - one can get kicked on the hand - but my gassers from 40 to 210 and all sizes in between act the same way.
I would appreciate any additional input on this.
(even ranting and raving )