Re: Fuel Efficiency 40hp "Big Twin guys"
Well, now you're discovering the Big Twins' Big Secret. They're not very fuel efficient. If they're running right, you should be able to cruise for a couple of hours on the 6-gal tank. At wide open throttle, you'll do worse than that. I run mine at about 75%, which seems to be its sweet spot.<br /><br />If I'm going to be out all day, I load a second 6 gal. tank in the boat and just switch connectors on the engine to the second tank at some point. If you do it right, you can switch tanks without shutting the engine down, since it will run a while on the fuel in the carb bowl.<br /><br />Now, you say yours is running "pretty well." If it's running perfectly, you'll get better fuel economy. As long as it's not flooding due to a bad needle and seat in the carb or a bad float, you can adjust the carb's high speed jet (if you have an adjustable one) for best performance and economy. I'm not sure when they changed to the fixed jet carb, though, so you may not have the high speed adjustment.<br /><br />What I figure for my 35hp is that I can fish for half a day without worrying about running out of fuel. But that's fishing, so I'm trolling or have the engine off most of the time. Even trolling, though, uses fuel at an alarming rate.<br /><br />You'll figure out how far you can go. But, with the plastic fuel tanks not being all that expensive, even with a second hose and bulb, the best bet is a second tank for those days you'll be on the water for hours.
