I just bought a 1989 Chaparral 198CXL 2 weeks ago. Gas spills out the relief vent when I'm filling it up. I have no warning when it's going to do this. Also, this afternoon as I was heading out to work, I noticed that there was gas spilled on the driveway beneath the boat. Apparently the hot day caused the tank to pressurize, causing gas to spill out the vent. It made a mess out of the side of the boat and lifted the striping from the side. Any ideas for a fix would be greatly appreciated. Thanks.