Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

I'd say the answer is yes to your question.  Ariens lists your Tecumseh at 8.5 HP.  I have that same engine on my Toro 828 LXE and Toro sells it as an 8 HP.  Ben, one of our forum members, was able to check the operating RPM for me on his Ariens and found it to be running at 3,450 RPM's, where mine was originally running at 3,300 RPM's.  The 150 RPM difference is why they are rating these engines at two different HP's.  Originally I thought these engines to be 9 HP L-heads derated by the snowblower manufacturer to what you see them labeled at. 

What has been very interesting is that Fred and Ben both have been insisting that these engines are actually an 11 HP derated for marketing purposes.  What I've done this past week is check the internal specifications taken directly from my Tecumseh Technician's Handbook, which is the actual manual you would use to service the internals of all 3 to 11 HP 4 cycle L-head engines.  It shows that the 10 and 11 HP L-head engines have a slightly larger bore by 0.187"  I can tell you for a fact that this minor difference shows me that on a dyno, all these engines would produce basically the same horse power. 

The restrictive muffler on all our OPE engines, just to name one thing, is what really keeps them from producing very much power, especially running in the mid-3,000 RPM range.  The only way you are going to move up in HP and torque is to move up to a twin cylinder engine, but those are not offered on snowblowers.  People think just by boring or honing a cylinder say, 0.020" will turn it into a super engine.  Well, that isn't the case especially on these single cylinder engines.  Think about how small that amount is, basically two-thirds less than the spark plug gap is on your car engine.

I'm very happy I didn't waste another $400.00 on the top 11 HP OHV engine offered by Toro, even that engine has exactly the same displacement as my L-head engine and tells me a lot.  I'd get yourself a good digital Tach/Hour meter for your machine and reset the governed speed up to 3,600 RPM's and it'll put you on an even playing field with what is considered a higher HP engine.  I'm convinced this is what has been going on and how to beat them at their own game.  I'd wait until the engine is broken in after the first oil change.  Switch over to Mobil 1 oil too at that time.