ORIGINAL: caesar148
What is the difference between the Thunder Tiger Pro and GP? From what I know the GP is a plain bearing engine while the Pro is a dual bearing. You might expect the Pro to be a better engine but the GP is of higher power and lighter than the Pro. To top it off, it cost less. It seems like the GP is an obvious choice over the Pro but am I missing something or is the Pro all marketing hog wash.
In addition to the bushing vs bearing difference, the GP series has air bleed carburetors and the PRO series has dual needle carburetors. I don't have enough experience to know how significant the carburetor difference is. My engines all have the dual needle design.
I have read that bushing engines need more castor oil in the fuel than ball bearing engines but I have no idea if that is fact.
My brother had a GP42 that ran great. It had a nice slow idle and probably would have idled for an hour if you wanted it to. It transitioned well and ran nicely at all throttle settings. He donated it to the club to go on a trainer.