Yes it is normal....The intake is restrictive...There are many posts and pics of people doing dual intake hoses to solve this problem...Just a note though,if it runs good with the lid on,and doesn't sputter,chances are you are running lean when you remove the lid...If you run it with the lid off,you need to increase the size of your main jet in the carb....Otherwise you will melt your piston or sieze the engine....
Hoodlum