I've read several of the posts on vented gas caps but still have a question. As many of you know I just finished installing a new engine. The builder had a rubber gas line from the pump to the carb (not good). After driving it a few miles today I started having idle issues. Got it home, parked it and tried restarting and just cranked for a long time till it started up again. I figued vapor lock or fuel percolation. So I decided to install the stock pump and connect the return line and use the hard line to the carb. I also put a thicker carb gasket on. When I disconnected the gas line from the pump, gas squirted everywhere with pressure. I quickly clamped it off then opened the gas cap. Wooosh.. a lot of vacuum there. I have the vented gas cap (repo). My question is shouldnt a vented gas cap not allow a vacuum to build up like it did? Or will reconnecting the return line cure the problem? Thoughts? Thanks!
