What is the on/off lever on the fuel cap for? I assume it is a vent of some form. I have two 84 TRX200's and one will sometimes die and will not start back. Once it died today the lever was ON. After checking for spark, which it had, and sitting a while, I switch the lever to OFF. I could hear fuel draining to the carb. It started and ran great after that. Is this lever some type of vent and I am just getting a vapor lock? The other quad never has had this problem but the cap on it may not work.