Q:My boat's fuel tank holds about 35 gallons. This season I've noticed that it's difficult to add fuel to the tank. At my marina the auto-shutoff keeps kicking in. I've removed the vent exit while fueling but haven't had any luck. Any ideas? BARRY RAY KILLEN, AL
A: First things first: Are you using the exact same pump and nozzle as last season? Did your marina install new gas pumps or nozzles? Does this occur everywhere you fill up? If this fueling problem started all of a sudden and you can't blame the gas pump, there could be a problem with the vent line or fill hose. Open the boat and get a gander at the large fill hose. That's the one that goes from the deck fill fitting to the tank. Check for kinks or bends that would cause the gas to back up. If it looks okay, move on to the vent hose, which meanders from the tank to the topside fitting. Disconnect the hose and blow. Do you notice any restriction or resistance? You'd be surprised at what could be lurking in the hose. Wasps and yellow jackets, for example, often make hoses home. Then there's the vent fitting itself. If you look closely, you'll see a wire-mesh screen inside the opening. It's a flame arrester. If it gets corroded, it can restrict airflow and make the tank difficult to fill. The entire fitting should be replaced if the screen gets corroded. I've got a feeling, however, that your boat hasn't changed; the marina most likely installed new pumps or nozzles and that's what's causing the trouble.
Q: I have a 20' cuddy cabin with a 4.3L MerCruiser Alpha One V-6 stern drive. If I have more than two passengers onboard, the boat won't plane. I'm currently running a 14"-by-19" prop. According to the sticker, the WOT range is 4400 to 4800 rpm. My engine runs between 5200 to 5500 rpm at WOT. Should I change to a 21" pitch prop? ED ZIEMBA RIVERVIEW, MI
A: Unless the hub is slipping, you've got to change the prop - soon. Running an engine with a prop that's too small for it is bad news. Save yourself some time and money and start with a 23" wheel right away. I think you'll find it fits just right. As a rule of thumb, for every inch of pitch increased, WOT rpm decreases by 150 to 200.