Four Stroke concern...
I don't have a lot of experience with four stroke engines. I have a ThunderTiger .54 mounted in a Sig Rascal .40 turning an APC 11X5. I do not have any tach numbers. I replaced the air bleed carb with the newer twin needle carb and find I'm using very little of the barrel travel to achieve "normal" operation from idle to what I think is full throttle. Full throttle "sounds" like it is producing full power... Throttle operation is not linear and uses quite a bit of expo to operate at what I consider normal for a two stroke. The airplane will loop from level flight but can't hold verticals for very long. Can anybody tell me if there is a problem based on what I'm seeing or is this considered normal performance?