Make sure your pilot screw is properley adjusted. When I put the jst kit in I arbitrarily opened the pilot screws 1/2 turn. Milage dropped to 36-38mpg. Starting was hard, chocking would flood the motor. Returning to the stock settings fixed the problem.

 

Also if you mpg is too high, it means you're not twisting the throttle hard enough.

If this condition continues for too long, it can result in your ********* shrivelling up and even dropping off. You have been warned!