I zip tied my throttle spring after the "break-in period" and when I got it near full throttle started backfiring a lot... OOW btw... My bro said it was the rev-limmitter kicking in and that it would be fine in the water... What are yalls thoughts? Going to run it in water tomorrow!

That is probably because you have too many coils on the spring tied up, and the valves are floating from turning too many rpm's. I'd reduce the amount of coils you have wrapped together, or you could just adjust the governor and throttle cable to turn the proper rpms.