In reading through this post, I try not to be bias, but couldn't help thinking of the head ache's I had had with using the perry pump
on a OS 120AX 2-stroke.... I had tried many of the sugestions but in the end, just removed it.
It ultimately (couldn't prove it) caused a head gasket, to MELT to the head.... Lean run? I just know that things were either
very touchy needle setings or non-responsive to needle changes....

It seems that 4-stroke engines are where all manufactures are placeing there R&D and, try the built-in pumps..
Obviously, we are talking about Alcohol/nitro/Glow engines, as gas doesn't have the same issues...
The price of a pump makes the price go up 100+$'s and I understand why others are willing to give it a 30$ perry pump try...
I am not so willing to tinker with this anymore, even though I was very determined to make the prevy setup work...

I recieved a New Engine out of the deal, and am running it in a QQ yak 54 69"... and I may be having fuel draw issues with the Tuned pipe installed
on it....I didn't get the chance to fly with the stock muffler, to compare, but this model would benifit from a fuel tank placed next to the Main wing tube, due to
dramatic change in CG when the fuel runs low.....

too cold to try it now, but maybe a Spring project...