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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AJace
I have an Ariens 926 Pro because I like Orange
Location: Near Gettysburg
Joined:
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Re: Tecumseh Engine Horse Power Rating Discovery
Reply #42 Jan 27, 2005 12:28 am |
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Sounding more like a dirty secret.  Here I was going to pay $400 for 3 more horses. Now I only have to pay $4-$14. Degrees, I'd second that carb.
Ariens 926 DLE Professional; Toro S200; Craftsman LT1000, Echo ES-230;
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Majorxlr8n
Location: Freehold NJ
Joined: Aug 6, 2003
Points: 1092
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Re: Tecumseh Engine Horse Power Rating Discovery
Reply #43 Jan 27, 2005 2:02 am |
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I covered this very subject in depth on the WTB Lawnmower forum...  I too searched & found out that there WERE different head/piston/connecting rod/carb combinations. That line the Tecumseh rep gave about jetting is HOGWASH. You guys are too quick to "jump on the bandwagon". Chris (Snowshoveller) is the only one besides me that realizes this. On a single cylinder, small cubic inch (15 ci?) OPE engine, you just aren't going to pick up TWO or THREE HORSEPOWER by a jetting change. NO WAY. I've changed jetting on automotive engines & dynoed them - I have found that I never gained more than 10-15hp on a properly carburated engine. These engines were all in excess of 400 cubic inches, mostly Pontiacs (400, 406, 428, 434, 440, 455, 462, 473, 480, 496ci) powerplants. Those "odd numbered" ci displacements are different rod/stroke/piston height/crankshafts to obtain some LARGE displacements, and better rod/stroke ratios for high RPM drag engines (6500 RPM+). These Tecumseh's have about 15 cubic inches, so I want someone to provide me with PROOF that a jetting change can yield 2 or 3 more HP on such a small engine. Its done by changing a COMBINATION of other engine components that will change: compression ratio, head flow, higher CFM carb (CFM=cubic feet per minute, a measurement of airflow). These items will provide a small, believable hp increase. Carb jetting alone on a one-lunged engine will not. Mods - if you can go back (if possible) to WTB & obtain the thread where I posted my findings, it may shed some light here. I spent quite a bit of time researching this & wish not to "reinvent the wheel". Nuff said... Marty 
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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 #44 Jan 27, 2005 6:56 am |
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Preliminary findings means just that. But thus far, its seeming correct for the most part. I think were Snowshoveler is going to find a slight difference is in the cubic inches or CC's of at least one version of the 11 hp, either L-head or OHV. We are not talking about 15 cu. in., rather 19.43 cu. or 318 cc's on the 8-10 hp and I believe 21.82 cu. in. or 357.58 cc's on say, an 11 hp. Governed RPM seems to vary widely as well. From as low as 3,150 RPM's to as high as 3,700. Whether you have an alternator for lighting or battery charging requires a different governed setting as opposed to an engine without those features. These engines also run at only about 50% of what they are capable of which is in the mid 3,000 RPM range. If anything, this is all very interesting and has turned out to be a great discussion. In the end, Snow is our only insider here having access to information that will solve all of this. When he's done looking into this, I'll go by his decision whether confirming or tossing all of this out.
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 #49 Jan 27, 2005 9:02 pm |
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Even if its THIRTY cubic inches, a jetting change will NOT yield 2 or 3 hp...  Nobody has said it would. To keep confusion, if any, to a minimum, I was correcting the 15 cu. in. in your post to exactly what engine sizes are in question.
Richie
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Thanks for your time and energy spent on this. You all are teaching me things here.