Re: Fuel Tank plumbing
As a sort of rule of thumb you can consider that any carburated outboard engine will burn fuel at WOT at a rate equal to 10% of the rated horsepower. So you can figure your 110hp. engine will burn 11 gallons per hour if you go fast all the time and about three quarters of that if you just drive the boat sanely, figure 9 gallons per hour at cruise and 1 GPH at what I would call trolling speeds. Short story is you can never carry too much gas on a boat.<br /><br />As for the plumbing you simply run flexible gas line. I know there is some sort of fireproof Coast Guard rating but I've always used the stuff they sell at the auto parts store. You screw an anti-siphon valve into the tank and slide the hose over its end. The anti-siphon valve looks like an aluminum hose barb with a big ball inside. West Marine sells a 3-way valve just for the purpose of connecting two tanks into a single fuel line. Do not run a line from each of the tanks to a T-fitting in the hope that they will drain equally - - they will not do it. Anyway that valve costs about $25 as I recall. <br /><br />They also make a 4 way if you have 3 tanks, which is probably what you are going to end up with if you really want to cruise all day. <br /><br />We have 3 tanks using a 4-way valve. I like the setup. Our boat had an 80 gallon tank in it when we bought it. That severly limited our fishing time so I added a pair of 18 gallon side tanks. So now we can fish as long as we like and still come back home with a rational reserve. The weight of our tanks isn't enough to make a noticable effect on the ride of the boat, and we have tabs anyway, so it doesn't matter much if we run one side tank dry before going to the other. The truth is I try to alternate which tanks see use but given a choice I'll empth the main tank first just because it is farther aft and I like to get some of the weight off the rear end of the boat early in the day if I can.<br /><br />Oh, after you get to the 3-way valve I really would recommend that you install a Racor if you don't already have some sort of drainable filter/seperator. After that would come the sensor for a fuel flow meter if you have one and then on to the primer bulb and finally the engine. Don't run the hose in close proximity to any electrical wires. Support it just as you would an electrical cable though. I like to tie the hose down as frequently as possible so that it can't get tossed around. Just keep your eyes open and think about safety as you route the hose. You don't want it chaffing from vibration and you need to be thinking about that would happen if it leaked. Make sure nothing will crush it like a closing hatch. It happens. Be careful with the vents too. If you put in another tank let me suggest that you go straight to the anti-siphon black vents by Attwood. They are the only ones I've seen that I know won't ingest water (well, almost the only ones). Plan for long slooping curves in the hoses if you can for a new tank and make sure the hoses don't come in contact with protruding pointed ends of screws down deep inside the hull..<br /><br />Thom
