ifuwill

I recently purchased a new 305cc OHV Briggs and Stratton powered snowblower. I was looking for the throttle control and discovered there is none.
My previous snowblower was a 3 year old 10.5 Tecumseh which I sold because I had heard that the OHV's were quieter, cleaner and smoother.
I always smelled like smoke after using the old machine in addition to the noise, occasional sputtering and back firing especially when the throttle was decreased and increased.
I have read on other forums that the reason for the missing throttle control is for EPA requirements, and that all Briggs and Strattons are the same now.
Can anyone elaborate please?
Thanks Cam

Basementgeek

hi and welcome to the forum

I think you will find that it depends upon the application the engine is used for. I just checked 3 snow blowers and none of them have a user controlled throttle. There is a "throttle" but it is automatic. It will increase the throttle opening a little when it needs to.

Snow blowers need to run fast in order throw the snow, there is no need for a user throttle, to slow it down. Granted, a light snow fall it could be nice to slow it down a little.

BG

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ifuwill

Thanks for the reply.
I spent quite a bit of time on the phone today researching this topic.
It would appear that with the demise of Tecumseh a lot of the suppliers are switching to Briggs and Stratton engines. I called Home Depot and Wal Mart to name a few and it sounds like all their machines are throttle-less as well. I also called the Briggs and Stratton representative and he informed me that all the bigger machines have the stationary throttles but have governors that maintain the power through heavy snow. He agreed with you that machines should be run at full power through heavy snow and that some customers were trying to do this at lower power settings and sometimes damaging components. But he said it was mainly because of the tightening EPA requirements and that these engines meet strict California emmisions requirements now. Some of the smaller machines (5 HP) may still have throttle contol. My machine is manufactured by MTD Canada Ltd who also manufacture White, Bolens, Cadet ,Yardman, Yardworks, and Troy-bilt to name a few. All seem to have the same type of engines as well. The other thing that I've discovered is that everything now is listed in LBS/FT torque as opposed to the HP rating. So my machine is rated at 1450 LBS/FT which I have been told is approximately 11 HP.
I guess it's just something we will have to get used to.

MrChooks

This foot pounds BS is a major PiA - Kilowatts was bad enough (I was the last year (1974) at Mining Engineering that was trained in imperial measure (lbs, gallon, feet horsepower etc) and converting to metric Kw, newtons, metres litres etc. is still a PiA to me. so having only just got used to going to Kw from HP - starting all over again with pounds feet or even worse, newton metres will have me in the loonie bin

Not wanting to sound like a smart-**** - but for those "desperates" who might be interested - here is how you go from foot pounds > horse power. (I plaged the article below from "How Stuff Works" ) and for the "purists" who want kilowatts - there are 746 watts in a horse power and lastly - in case anyone is interested - if you made a horse do a horsepower of work - (ie carry 550 lbs at a speed of a foot per second) you would almost certainly KILL IT!


You can calculate how many foot-pounds of horsepower an engine produces using a common equation:

(Torque x Engine speed) / 5,252 = Horsepower
The engine that makes 300 pound-feet of torque at 4,000 RPM produces [(300 x 4,000) / 5,252] 228 horsepower at 4,000 RPM. But where does the number 5,252 come from?

To get from pound-feet of torque to horsepower, you need to go through a few conversions. The number 5,252 is the result of lumping several different conversion factors together into one number.

First, 1 horsepower is defined as 550 foot-pounds per second. The units of torque are pound-feet. So to get from torque to horsepower, you need the "per second" term. You get that by multiplying the torque by the engine speed.

But engine speed is normally referred to in revolutions per minute (RPM). Since we want a "per second," we need to convert RPMs to "something per second." The seconds are easy -- we just divide by 60 to get from minutes to seconds. Now what we need is a dimensionless unit for revolutions: a radian. A radian is actually a ratio of the length of an arc divided by the length of a radius, so the units of length cancel out and you're left with a dimensionless measure.

You can think of a revolution as a measurement of an angle. One revolution is 360 degrees of a circle. Since the circumference of a circle is (2 x pi x radius), there are 2-pi radians in a revolution. To convert revolutions per minute to radians per second, you multiply RPM by (2-pi/60), which equals 0.10472 radians per second. This gives us the "per second" we need to calculate horsepower.

Let's put this all together. We need to get to horsepower, which is 550 foot-pounds per second, using torque (pound-feet) and engine speed (RPM). If we divide the 550 foot-pounds by the 0.10472 radians per second (engine speed), we get 550/0.10472, which equals 5,252.

So if you multiply torque (in pound-feet) by engine speed (in RPM) and divide the product by 5,252, RPM is converted to "radians per second" and you can get from torque to horsepower -- from "pound-feet" to "foot-pounds per second."

Basementgeek

Good to know that you got the questioned answered, about the EPA thing.
The EPA is more concerned about keeping the air clean than they are about you blowing off the drive.

The snow blowers I have are any were from about 12 to 25 years old.
The are all smaller engines 2.5 hp to 5 hp and as I have stated there is no throttle on them.

Thanks for the excellent info Mr Chooks, now to remember it

Is that for a 2 cycle engine or a 4 cycle

BG

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MrChooks

BG - "how to remember it" has always been my problem - that's why I am so antagonistic to system changes - especially ones that seem to serve no useful purpose - and simply confuse a perfectly workable definition / description that all & sundry understand, by replacing it with one that only the "academics" understand

On the 2 stroke / 4 stroke issue - I guess if you just add a few drops of oil to the calculation sheet the answer will come out OK

k2skier

The reason Briggs & Stratton did away with HP ratings, (what they told us last year in the update school anyway) was because of a law suit against Sears. As MrChooks showed how HP is calculated, all someone in marketing has to do is say "we can run this engine at 4500 RPM's" (when the max is 3600) "nd we can get 7.25HP out of this 6HP engine", which is completely false and misleading advertising. In the industry it was called relabeling or restickering. And as for a throttle; why would anyone want to idle an engine? A throttle makes the equipment cost more, it's another part to break and an engine runs under load more efficiently at full throttle. It's not very common to see throttles any more.