KGSS28,

I owned the Webra that was commented on in this post several years ago. Horizon told me the Webra pump was a problem due to inconsistencies in quality control. That's why some ran good while others made you pull your hair. I have learned from flying with an expert engine man here in Phoenix always run a 1oz header tank on all pumped engines. This takes some of the load off the pump and makes for a more consistent run down to the last oz of fuel. I have incorp this into my latest OS140 setup and I can tell the difference in the way the engine performs. The engine seems to strain less probably because the fuel is pulled from the header tank 3 inches from the carb instead of 12 inches from the CG location. This would be a easy thing to try vrs tinkering with the pump settings. I've been there and done that on a Webra and ended up solving nothing. Good luck and remember - make small adjustments at a time if you mess with the pump. Webra's are very intollerant of heat so make sure your cowling provides excellent airflow.

M Austin