49cc 2 stroke engine won't start, so I took the carb and the exhaust off. Pulled the plug out. Pulled the pull start and gas vapor shoots out the intake port where the carb would be, so I pulled again until it stopped shooting out the vapor. Then I looked into the intake port and noticed that when the piston is at the bottom of it's stroke the chamber isn't open to the intake. I can see the upper piston ring but no opening to the chamber. Is this normal?