Outboard or Stern Drive I/O for the boat show

2012 boat photo Yamaha outboard

The cleanest engines are the inboard / outboards. They come with Catalytic Converters and other tweaks to get a 4 star rating as compared to a 3 star rating for the outboards. Which means that the outboard engines are the “worst for the environment” engines compared to I/O power packages.

It is surprising that the 2 stroke Evinrude and the newest 4 stroke Yamaha are both equally rated at 3 stars. The I/O engine packages have simply pulled ahead of the outboard packages for 2012 for the cleanest level in environmental boating.

Evinrude makes the lightest outboard engine package at a stated weight of 524 lbs. for a 250 Horsepower engine. It’s a 200 cu. in. two stroke engine. It should be propped to run between 4,500 – 5,800 rpms. Some say it’s the least complicated and has the lowest number of parts. And it may take the least attention and maintenance over a season of use.

Yamaha makes a F250 Offshore outboard that is a four stroke engine. It has a stated weight of 562 lbs. It also has more parts (pretty much all the valves and camshaft parts) than a two stroke. The displacement is 254 cu. in. I cannot tell if the smaller displacement two stroke will be faster in a 0 to 30 mph acceleration test than the bigger cu. in. 4 stroke outboard, but in similar displacement two strokes compared to similar displacement four strokes tests show the two strokes really beating the four stroke.

2012 boat photo evinrude outboard motor

The stern drive I/O is a four stroke 305 cu. in. engine based on a Chevy block that is then made into a marine engine by Volvo – Penta. It has a horsepower of 270 and can come with the efficiency of two propellers on one shaft in its Duo-Prop Stern Drive. This one weights in right at 1,000 lbs.

2012 boat photo volvo penta inboard outboard engine

It is important to note that both the torque and the peak horsepower are at a 1,000 rpms lower than the outboards.

So, a cleaner for the environment drive package. Lower engine rpms needed to get a boat up on plane and at a cruising speed. Some more weight within the power package. The I/O choice of the efficiency of a Duo-Prop outdrive. All of this says that a I/O is the way to go in 2012 for seabuddy.

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