You do need to vent the tank. If you drive and the gas in the tank can't vaporize fast enough to replace the gas you use running the engine, you can crush the tank from the vacume.
The oposite is also true: I had a 87 Dodge Caravan with the wonderful (POS) Mitsubishi 2.6L motor with that "interesting" Mikuni carb that had a bad vent line. The heat from the hot exhaust and the hot summer sun caused the gas to expand which filled the intake and a cylinder with raw gas. There is nothing better on a hot afternoon than to relize you just hydrolocked the motor while you where in the mall shopping! Gas will also leak past the rings and dilute your motor oil too!
Karl
80 CJ/YJ-7 FrankenJeep
94 Grand Cherokee
The oposite is also true: I had a 87 Dodge Caravan with the wonderful (POS) Mitsubishi 2.6L motor with that "interesting" Mikuni carb that had a bad vent line. The heat from the hot exhaust and the hot summer sun caused the gas to expand which filled the intake and a cylinder with raw gas. There is nothing better on a hot afternoon than to relize you just hydrolocked the motor while you where in the mall shopping! Gas will also leak past the rings and dilute your motor oil too!
Karl
80 CJ/YJ-7 FrankenJeep
94 Grand Cherokee
