The Yamaha 300 HPDI outboard is worthy of a test and review even in this day of four stroke dominance, because this is one two stroke that packs a heck of a punch and will be of interest to anglers. Why? Haven’t four strokes completely taken over, especially considering Yamaha’s new line of SHO’s which have the light weight and acceleration of a two stroke? Almost, but not entirely. Many guys want to stick with twos in this size range because the new four stroke SHO’s only go up to 250 horses, and even with 50 fewer horses, cost significantly more than the HPDI’s. On top of that, to put it bluntly, many fishermen are simply set in their ways and have a hard time changing over.
The 300 HPDI is a 3.3 liter 76 degree block that has a 3.66 bore x 3.23 stroke, six throttle valves, and six high pressure direct injectors that push fuel at 1,000 psi. It has a 50-amp alternator, a pair of high-speed fuel pumps, and an extremely low water intake which allows mounting on a jack plate or elevated transom bracket. The brain of the beast is a TCI microcomputer.
The HPDI weighs in at 539 pounds, which gives it the best horsepower-to-weight ratio in its class at .56 hp/lb. And you’ll feel the net result when you slam down the throttles. I first tested a 300 on a 22′ bay boat, and to say the acelleration was “head-snapping” would not be an exaggeration. Time to plane was too fast to accurately measure with my thumb and a stopwatch, and at wide-open throttle we blew past 60-mph and would have kept going, were it not for a chop that sent us airborne every time we tried to open it up all the way. Down sides? It was louder then a four stroke (though not as loud as an old-tech two) and it needs to be fed a steady diet of two-stroke oil. I also caught a whiff of smoke on occasion, though it’s greatly reduced from the old two stroke days.
Will the 300 HPDI survive in the age of the four-stroke? It’s a coin toss. If (should we say when?) Yamaha expands the four stroke SHO line to include 300 horses, the HPDI’s days could be numbered. But up until then, if you want 300 horses with a kickin’ hole shot and top-end at a reasonable price (plan on spending around $20K), the HPDI needs to be on your short list.