Last summer i bought a Clinton model 414 engine. On it somebody had made a intake and mounted a Keihin carb on it. It is a slide valve side draft carb. The number stamped on the Keihin carb PE---45BATK. The letters PE are cast into the upper half of the carb and the number 45BATK is stamped on a boss just below it. The carb just looks to big for the Clinton engine. Any idea what Carbzilla fits ? Also what is the plunger on the top for ? A choke maybe.