14+mpg on my 86' carbureted D-250 with a 6x12 single axle trailer, headed for 15 and I am a NUT about fuel mileage.
What has helped:
Nothing goes with me that is not being used that day. I see MANY Lco's headed down the street with trailers loaded like they're carrying the entire store - That's like 500 - 1000 pounds extra weight, you won't see MY truck or trailer like that, it's so empty it's almost eerie.
Plan ALL the same kind of work for every whole day... i.e.: Monday - ALL day grass-cutting, Tuesday - ALL day mulch, etc. - Load / Unload what you need the night before and leave everything else at home. The labor spent in doing this is saved in money at the pump.
Learn to drive using ONLY the gas pedal to control your vehicle. Do NOT use the brakes but coast a lot instead, I got so good at this I hardly ever touch the brakes until I'm down to 20mph or below - When a light is red and coming up a ways ahead, I can and WILL hit the brakes at 45 mph to take the truck into the 30's so I can mosey on down the road and usually the light turns green in this time and I never have to stop... Half the time I can do this by just letting off the gas, the brake is for emergencies only. NO do not think reckless driving, think SLOW driving, think COAST.
Another way to say it is: Braking converts speed into HEAT, and it took FUEL to build the speed in the first place! Thus, letting off the gas earlier helps save fuel! It also makes my brake pads last well beyond 100,000 miles/set.
One more thing I start out from a stop real easy, it can take 5 miles before I see the speed limit if I ever see it. The speed limit does not concern me, with my truck, the slower and easier I drive, the better the fuel mileage - Taking back roads and less-trafficked routes helps. Ppls already figure us for slow-moving vehicles, so, play the game and everybody's happy.
Took off the tailgate, installed Taylor 8mm Hi-performance wires, installed Hi-performance cap+rotor AND hi-performance air filter - OMG! Another thing helps is a Hi-performance Ignition coil thou for some reason on the Dodge it cross-fires... One other thing is dual exhaust with headers but this costs around 600 dollars...
NEVER take spare equipment with me - Even thou I have two of most everything (blowers, trimmers, wb's, etc), only ONE lawnmower comes with me on any given day, it's either the new one or the old one - I don't play with Ztr's and pushmowers and then a Wb to boot: ONE 48" mower, that's all I need.
Switched from a floating deck Wb to a fixed deck - 200 pounds less.
ALWAYS fill everything up the night before and leave the gas cans at home. The Wb lasts ALL day on a tank, most the 2-cyclers do, too, thou I do carry a quart of mix fuel (an old oil bottle filled with mix) AND a syphon hose with an empty can because the Wb can fuel the truck and vice versa in an emergency (which has never happened).
