ORIGINAL: johntammi
I get it tuned pretty good where it responds clean and strong but dies after running a high rpm for over a minute. I was thinking if I should get a new hsn assembly. Horizon said to ship the motor back to them, will having taking the limiter off affect the warranty?
Dying after a while at a constant throttle setting tends to indicate that the air/fuel mixture is overly rich at that point.... which goes hand in hand with your other observations.
You may need to lean out the high speed a bit, then go back and work on the low speed, which will then be off again.