Re: HP & Torque Curves for 9.9 & 15 hp
OMC was known for false advertizing and their engines were so pooly designed that this model could not quite make 10HP, so they rated it at 9.9 HP instead.
The 15 HP was a flat out lie, OMC intentionally did this to misslead buyers!
Not really, just kidding.
If OMC rated an engine, it was BIA certified to produce at a minimum the stated power. OMC submitted their engines for BIA testing, so it was certified by an independant authority, this means there was, and still is actual credible test data prooving they were able to produce the manufacturers stated horse power. You should contact BIA if you have more questions, as they are the certifying authority.
Please note OMC always stated a lower RPM where the horse power was taken at, yet they usually are capable of up to 1000 RPM more at full throttle as shown by the maximum full throttle RPM specification, so they had power to spare.
A rough rule of thumb for small 2-cycle engines is you have about 1 horse power per 0.61 cubic inches (10cc) on an industrial engine, twice that for a racing engine. At 216cc, the 9.9/15 is easily capable of this, as it calculates out to haveing over 20 hHP given it's displacement, but it is highly restricted, even with the bigger carb. This is so if you hold it wide open, it will run all day. On my 200cc twin cylinder motorcycle engine, it has two carbs, and just one of them is bigger bore than the 15 carb, so this gives you an idea how under carbureted all outboards are in general, and this is so they will run wide open all day. Take a look at how big the carbs are on equivalent sized small APBA racing engines, and the kind of power they produce and it all becomes quite clear this engine is way overbuilt and has additional power to spare. The problem is it will not last as long if you tap into that power.
