Yamaha introduced a new F25 outboard earlier this year, and recently we had the chance to spend a day with one out on the water. The engine was mounted on the transom of an AlumaCraft Escape 145, a small and simple aluminum fishing skiff that’s an ideal match for this engine. The strange thing is where we went to perform this testing: would you believe, Wisconsin? Well, it’s true. And although those waters are quite different than Texan stomping grounds, the opportunity to run the engine was well worth the trip – plus, we got to try fried cheese curds. For real.
The big take-away from the Yamaha event was that the F25 is a significantly different – and much improved – engine as compared to last year’s model. For starters, the engine is much, much lighter. In fact, at 136 pounds, this is the lightest 25 horsepower outboard engine on the water today and it’s about 25-percent lighter than last year’s F25. It’s also smaller, overall, in every dimension.
Here are some important specifications and features: the powerhead has 2.56” bore x 2.56” stroke, displaces 432cc, and has a compression ratio of 9.3:1. It has an external flush port, plus built-in carry handles and rest pads. Yamaha’s oil-retention system keeps things leak-free when the engine is laid down in the back of a pick-up or SUV, so moving and storing the engine is easier than in the past. And the alternator puts out 16 amps. Above and beyond all of these features, however, the most important thing to keep in mind is the battery-less EFI system utilized on the F25. Yamaha isn’t the first to have battery-less EFI, but it’s a fairly new development for small outboards and is a welcome improvement. Since the system is pressurized and the fuel isn’t exposed to the air, you can forget about all the most common ethanol problems like gunky, clogged carburetors. The engine starts on the first pull (just as long as you pull the chord all the way; we noticed that when we got lazy and didn’t get it all the way out, a second pull was necessary) and efficiency gets the usual boost as compared to carbureted engines.
Speaking of efficiency, one of the big shockers with this engine is that efficiency only seems to get better the harder you run it. The very best fuel economy comes at 5500 rpm, where it burns 1.8 gallons per hour to get 12.1 miles per hour. But even at wide-open throttle (6100 rpm, in this case) the boat still gets 10.4 miles to the gallon. This is important, since the fact is that with small outboards like these, most people run the engine at WOT on a regular basis. If you’d like to see the F25 in action and check out the full range of performance, check out this short video from Wisconsin:
For more details on the F25, visit Yamaha.