posted 08-01-2015 11:56 AM ET (US)
Typically there are models in the outboard engine line of most manufacturers that are designated with some sort of label that suggest they have more power or run faster. These models sell at a premium price compared to their companion engines of the same rated horsepower. In some cases these models have larger displacement. In some cases they are tuned for maximum speeds, although exactly what that means is nebulous. Boat speed is a function of horsepower, and if a boat goes faster with a particular engine the most reasonable conclusion is that engine has more horsepower.Whether or not the premium price charged for the enhanced model is worth its greater cost in the production of greater boat speed remains to be evaluated by the buyer. If your goal is to get the maximum boat speed with an engine whose horsepower decal says "150", then look at one of the enhanced 150-HP models. Compare the cost to the standard 150-HP. Then decide if going 1-MPH or 2-MPH faster is worth the cost. Decide how often you will be operating the boat at full throttle and want to coax out another 1-MPH or 2-MPH in boat speed.
For some boaters, the allure of having some sort of special cowling decal and special cowling ornamentation designating their engine as a special version distinct from the standard version is itself worth the premium price.
Regarding the ability of an engine to very rapidly accelerate a boat from a standing start, I have to wonder how important that really is to most boaters. I recall I was boating with a good friend who owned a beautiful OUTRAGE 25 that was over-powered with 400-HP. I was at the helm, and I asked him how the boat accelerated when you pushed the throttle to full from a standing start. At that point in time he had owned the boat for more than 15-years and had hundreds and hundred of hours operating it. I was quite surprised by his response. He said, "I don't know. I have never tried it."
I can't recall that I have ever tried accelerating from a standing start at full throttle with my boat, either. I just don't see any need to do it. About the only time the ability for a boat to accelerate extremely rapidly from a standing start is required is when being testing by some boating magazine for a performance report.
If you think that you will be frequently using your engine to accelerate your boat from a standing start at full throttle, then getting an engine with larger displacement will probably improve that acceleration. If that is important to you, then, again, the added cost of the the premium model might be justified.