Abby’s Guide > Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) > Discussions > Tecumseh Engine Horse Power Rating Discovery
Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions |
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Richie
 
Bring On The White Stuff
Location: Long Island, New York
Joined: Dec 12, 2003
Points: 562
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Tecumseh Engine Horse Power Rating Discovery
Original Message Jan 24, 2005 3:47 pm |
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Recently I installed a tach/hour meter on my Toro 828 LXE and found theat the maximum operating governed engine speed was 3,300 RPM spiking to 3,330 RPM's. I actually felt it was running a bit slowly but decided to use it, as is, immediately after it stopped snowing on Sunday. Well, we had about a foot of snow on the driveway with some 18" drifts, and the EOD was about 21", thanks to the snow plows. The machine handled it perfectly until I got to the EOD. While blowing through it, the Tecumseh engine wanted to stall. Nobody can tell me this is normal on a high end snowblower like this. It was 15 degrees and it was freshly plowed loose snow. If it had been wet, I would have been able to look past it. With all the research I've done in the last 24 hours, I am nearly convinced that the governed RPM set by the manufacurer may have much to do with the horse power rating they give them. The Tecumseh 9hp-11hp Snowking engines all vary greatly in governed RPM, as low as 3,350 up to 3,700 on the 11hp OHV version. When I see that the Tecumseh 9hp is 318cc's and the 11hp is also 318cc's, where are they getting these horse power ratings from. Making an engine OHV gives you that much more power? Well, I wasn't able to find the governed operating RPM for my Tec 8hp L-head engine, and given the wide margin of RPM's on their engines, I decided to raise the operating speed of mine to what I felt it should be. Initially I raised it to 3,600 as it was suggested to me to do, but I felt this was too fast by the way it sounded. So I then reduced it to 3,400 spiking to 3,430. Roughly 80-100 RPM's higher than what it was. The result of this, I took it out into the street to the 28" high, five foot across snow drifts left on the side of the street from the snowplows. These drifts are 8" higher than my auger housing. The sun was out and the snow was nice and moist, perfect for making snowballs. I raised the throttle to operating RPM, put it in 1st gear and off I sent it into the drift. The chute started to toss the snow some 40 feet across the road and you could now hear the engine under a load. The difference this time is that the engine was maintained speed and not a hint of it wanting to stall. In fact, the tires actually broke loose and I started pushing it into the drift to the point it began tunneling. The entire time the engine didn't faulter for a second and I actually felt I had a 10 hp engine on this great machine. What a difference a very small increase in governed engine RPM makes. At one point on Sunday I was upset with myself for not shelling out the extra money for Toro's top of the line 11 hp OHV version for over $1,600.00. Well, after how this experiment worked out, now I feel I just saved myself over $400.00 because this snowblower can go through anything now.
Richie
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Richie
Bring On The White Stuff
Location: Long Island, New York
Joined: Dec 12, 2003
Points: 562
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Re: Tecumseh Engine Horse Power Rating Discovery
Reply #4 Jan 24, 2005 4:41 pm |
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Hi Nibbler, Thanks for the concerns, I appreciate it. I really hope that members of this forum won't start playing with their governors as I have. It was not my intention to rally everyone to touch factory set components, not to mention warranty issues. However, I used to belong to the Long Island Karting association, racing sophisticated go-karts. My original class was the Briggs & Stratton class. You had to start with a 5hp aluminum block, remove the governors, which makes them rev out to 6,800 RPM's, blueprint and re-jet the carb to handle methanol and such. If you didn't rebuild these now very over-stressed engines, they would usually explode within weeks of removing the governors. However, since the day I purchased my Toro 828, I felt the engine was running slightly slow, and I mean slightly, at least to my ear. The tach/hour meter confirmed what my ears were telling me. I've looked everywhere for the engine specs, but can't find them. I even checked the Tecumseh Service Information book, nothing. Honestly, if this engine could really sustain any damage running about 80 RPM's over what the factory set it at, I think we all would be purchasing engines every year because they would be considered so fragile. I would love to know if I was correct or not, or if the 3,300 RPM's that it was set at is correct. I also made a mistake on the RPM range of all those engines in my first post. The governed operating RPM range is from 3,250 - 3,700 RPM's. A 10hp L-head runs at something like 3,600 RPM's. Sounds like a lot of RPM's for a snowblower. These questions have been asked so many times on this board, the old board too, I'm really looking into this HP issue because it's bugging me. I'm trying to find out if it's a different cylinder head, muffler, or simply carb jetting that gives them the majority of their HP rating. Thanks again, Nibbler for any help with this.
Richie
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Richie
Bring On The White Stuff
Location: Long Island, New York
Joined: Dec 12, 2003
Points: 562
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Re: Tecumseh Engine Horse Power Rating Discovery
Reply #5 Jan 24, 2005 4:44 pm |
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Hi AJace, Yes, it would be considered voiding the warranty, but I only turned the governor one complete turn. I know exactly where to put it back if an issue comes up. Truthfully, 80-100 RPM's was so little, you almost couldn't hear a difference in the engine. It's such a slight amount, even with a sharp ear, I had to check the RPM meter to know exactly how much it actually went up.
Richie
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Richie
Bring On The White Stuff
Location: Long Island, New York
Joined: Dec 12, 2003
Points: 562
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Re: Tecumseh Engine Horse Power Rating Discovery
Reply #10 Jan 24, 2005 5:32 pm |
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Hi there Marshall, I do believe OHV engines are more efficient, therefore afford you a better more powerful engine, especially in the area of low end torque. But how much extra do they afford an engine? From what I've seen, there appears to be a lot of playing with RPM from model to model. What are the manufacturers doing to these engines to increase their advertised horse power? If they are generally leaving the cubic centermeters the same, typically 318cc's, is simply increasing the operating RPM where a good portion of this horse power comes from? I know on 2-stroke engines I used to race, changing exhaust mufflers has a drastic impact on engine performance, from a snail to a jack-rabbit just by switching a "can" type muffler to a high performance tuned exhaust. JoGo, right now that seems to be the $64,000 question. I'd like to think it is that simple, but I'm not done investigating this to make a stand. I'm trying to get my hands on the exploded view manuals for some of these engines. I want to look at the carbs for starters, I'm curious if the jetting is the same, and I want to see if the heads are the same part numbers.
Richie
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Marshall
As Long As There Are Tests, There Will Be Prayer In Public Schools. ;- )
Joined: Sep 16, 2002
Points: 7730
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Re: Tecumseh Engine Horse Power Rating Discovery
Reply #11 Jan 24, 2005 6:03 pm |
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Hi there Marshall, I do believe OHV engines are more efficient, therefore afford you a better more powerful engine, especially in the area of low end torque. But how much extra do they afford an engine? From what I've seen, there appears to be a lot of playing with RPM from model to model. What are the manufacturers doing to these engines to increase their advertised horse power? If they are generally leaving the cubic centermeters the same, typically 318cc's, is simply increasing the operating RPM where a good portion of this horse power comes from? I know on 2-stroke engines I used to race, changing exhaust mufflers has a drastic impact on engine performance, from a snail to a jack-rabbit just by switching a "can" type muffler to a high performance tuned exhaust. JoGo, right now that seems to be the $64,000 question. I'd like to think it is that simple, but I'm not done investigating this to make a stand. I'm trying to get my hands on the exploded view manuals for some of these engines. I want to look at the carbs for starters, I'm curious if the jetting is the same, and I want to see if the heads are the same part numbers. Hi Richie, In Emmo's link it show's three different 9HP models of the same engine, running at three different RPM's. Although RPM's can effect how much HP an engine puts out, if it has the extra HP available, I don't think RPM's are what make or account for the extra horsepower on an engine rated at higher HP. So, I believe they are gaining extra HP through other means, be it OHV's, jetting, heads, breathing, pistons, exhuast, etc. Just my .02 cents.
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