I had a GT90 wasn't as tuff as advertise I learn never buy a racing motor. It's ported it's gonna blow a jug looks like thumb imprint maybe to prevent that is to drop your stock exhaust get one with more expansion.
The carb I like except you need a reed it blows back into the air filter clogs it power speed drops off rapidly your to wash it in clean gas every time you mix a 2 stroke gallon. So I just said f*** it took the reed off took the filter off runs just fine.
Next thing happen the motor just putter right out went over every day for a month junk the motor bought a stock made me happy again.
What I use for the drain tube small vacuumed line I think 3/16" the carb I like because you don't half to choke every time you get on it until the temperature is in the teens and if walk it flood it for 60 seconds 1 or 2 minutes before start it you can still bypass the choke.