There's a good chance the carb setting is fine and the problem is that the carb is defective and/or not engineered properly. It's not loading up when you tilt the model forward because it's set too rich...it's loading up because the carb isn't regulating the fuel properly or not at all.

What you'll likely find is that if you lean the low end enough so that it doesn't load up when you tilt the model forward then the engine will die of fuel starvation at when you tilt the nose UP. The term I use for such a condition is to describe the carb as being "tippy"...and therefore the engine becomes what I call a "test stand stud": runs great on a test stand, but can't really trust it in an airplane.


I'm hoping it's a manufacturing defect as I'm considering this motor myself. Contact Horizon, their cust service is excellent. Good luck.