and a fairly quiet resonating sound
Ok this sounds as if you may be going in the right direction. Was this with the tailpipe extension on?
Where was the stinger when you got this quiet resonating? (Diagram please)
We have certainly had motors running in Lockwood mode with quite a small dia. stinger - not at full power but well enough to demonstrate the correct fuel location.
The first things that come to mind now are, in no particular order:
Turbulence and mixing
- small motors the time allowed for this is very short as the overall cycle time is short. The critical area is where the induction pipe and the front cone into the combustion chamber meet.
Fuel pressure and flow rate
- on small motors it can be a little difficult to get starting values correct.
- One small Lockwood would only start when good and warm
Induction pipe lip
- The roll on the entrance to the induction pipe is very important. It can make the difference between it running and not.
Personally I'd start with the Induction pipe. Find someone with a Jenny (I think it's called) who can put a good roll on the induction lip, about 4-5mm radius. Then re run your tests.
Would you please detail for us your fuel delivery system up to the stinger? I have this idea that you are using a camping type stove.
I'm sure I've forgotten something - the good folks of this forum will correct me as they see fit. Remember make only one change at a time and keep notes.