I have an old Zuma that was sitting for five years. I went through the carb , replaced the pilot , needle and float . Also replaced the vacuum operated petcock . It starts and idles for a few moments , then dies , as if the bowl is running out of fuel . Does the air filter assembly need to be mounted ? I know some engines need it in place to run right . I have been in side the carb several times . All the orifices seem to be clean and flowing air . Any thoughts ?