I just finished breaking in the engine. This is the Email i just sent to mugen.
I am having several issues with the engine I purchased. I ordered the engine through A-Main hobbies and had several issues with the carb. Brand new engine and noticed some rust on the low speed needle. Didn't think anything of it so I installed the engine in the car with no issues. When I installed the throttle linkage on the uniball joint, the ball broke off before i could even get the ballend on. I replaced the Uniball Joint and my next issue was that the carb was binding. I took it apart and it still had flashing on the throttle barrel. I tried to remove the flashing which was scratching the inside of the throttle body. I polished the inside of the carb body and that reduced the binding but it was still there. Then I found that the idle screw was also causing binding. As I adjusted the idle screw, it cause the throttle barrel to rotate slightly causing more binding. Well I finally found what i thought was a happy medium on the idle screw, i started it up and ran the car a bit and then the engine locked up. When i took it apart, i found that the idle screw broke off right at the threads sending the rest of the tip through the engine. So I ordered a new carb through A-Main hobbies which should be here friday I hope at the cost of about $100. I just wanted to let you guys know that I am unsatisfied with the carb on this engine.Hopefully I recieved the only bad one and the new carb will work as designed.