# Newbie question: engine throttle



## fredct (Jan 9, 2017)

I just bought my first snow blower and got it set up. Reading the instructions I had a couple questions, including what should in done when the instructions say "set the throttle to the desired setting". I'm, okay, but what if I don't know what I do or should desire??

I googled around but didn't find much info. What I did find had people generally saying they ran wide open/fast. But when I called with my few questions the rep answered most satisfactorily... except that one. For that I was told I should be run it at slow. Butdidn't get much of an explanation as far as the pros and cons.

I always like to make an informed decision so I turn to you... what benefits do I get from running fast vs slow? Does fast literally move it (turn the wheels) faster? More power to the auger and impeller? What difference would I see? What's the benefit to running slower? Less wear in the engine? Lower gas consumption? What?


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## nastorino (Jan 28, 2016)

What brand and model?

Higher throttle position is going to allow the machine to do work with greater ease. In my opinion you're better off keeping the throttle up, aiming better, and angling down the chute. If necessary you could back off the throttle if that isn't sufficient. That would then decrease the throw range. 

Downside is going to be fuel consumption decreases with higher rpms.


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## Kiss4aFrog (Nov 3, 2013)

:welcome: to SBF fredct


I usually run mine at or close to full throttle as they seem to work better there.


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## sscotsman (Dec 8, 2010)

Small gas engines on lawnmowers, snowblowers, riding motors, rototillers, etc. should *Always* be run full throttle, max speed the throttle lever allows, when doing what they are supposed to do, for two reasons:

1. They are air-cooled. They are designed to run at full throttle for maximum cooling. Running them at half-throttle or slower (for an extended time, 5 minutes or more) can be dangerous and bad for the engine, causing the engine to over-heat and be potentially damaged. Running at full throttle is better for the engine's health, they were designed for it.

2. The machine the engine is attached to is better at doing its job when the engine is at full- throttle. Again, this is by design. The engineers who designed these machines knew what they were doing.

Yes, cooling isnt as big of a concern in the winter as it is in the summer...cooling is much more important for a lawn mower in the summer...but there is no reason *not* to run a snowblower at full throttle when blowing snow, it will work much better that way, and it wont hurt the engine at all.

Your "desired" throttle speeds are generally:

1. Starting position, usually 50% or 75% of max. Put it there when first starting the engine, start 'er up, then put it to full throttle after 5 to 10 seconds.

2. Blowing snow: full throttle, always..

3. Stopping, turning off the augers, bring the throttle down to 50% so you can hear better while your wife yells something to you from 20 feet away, thats fine for a minute or two, but put it back to full throttle when you resume.

4. Shutting it down for the day: slowly bring the throttle down, slowing down the engine over a 5 to 10 second span, until it shuts off. Or bring to lowest idle, and turn off with the key.

Scot


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## fredct (Jan 9, 2017)

Thanks everyone! I got a Cub Cadet 2X 26" HP. Very well rated in the places I looked and I got in a trial run after I set it up when it snowed this weekend (though I hadn't yet cancelled my plow so I didn't do the whole driveway). So far so good.

Scot, only thing you said that the manual
directly disagrees with is #1. It says to move it to full throttle (and full choke) before starting (I'm 99% sure... I'm heading to bed and I don't have the manual in front of me but I'll double check in the morning). Do you feel strongly enough about that that I should ignore the manual there?


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## fredct (Jan 9, 2017)

I did review the manual... it says to put the speed control on fast, set choke to full choke, press the primer bulb 3 to 5 times, pull the starter cord or run electric start, move the choke down once it runs smoothly until you're on no choke, and move the speed control to the "desired" position. It's an MTD engine.

Open to suggestions if people think I shouldn't start it on fast but of course I'd otherwise intend to follow the manual...

So it sounds so far like people say to run it on fast unless I'm idling for a bit. It's more power and actually better for the engine. The only pro of slower is it would use less gas? Any other perspectives?


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## Elt31987 (Sep 6, 2015)

The ONLY time i lower the throttle is when i need to stop the machine to hear better (Wife yelling out the window, Neighbor stopping by to say hi etc etc).


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## JD in NJ (Dec 21, 2016)

sscotsman said:


> Small gas engines on lawnmowers, snowblowers, riding motors, rototillers, etc. should *Always* be run full throttle, max speed the throttle lever allows, when doing what they are supposed to do, for two reasons:
> 
> 1. They are air-cooled. They are designed to run at full throttle for maximum cooling. Running them at half-throttle or slower (for an extended time, 5 minutes or more) can be dangerous and bad for the engine, causing the engine to over-heat and be potentially damaged. Running at full throttle is better for the engine's health, they were designed for it.
> 
> ...


Scot,

I don't think I understand you on point 1. At max throttle I would think they should be generating the most heat, seeing as there are more ignition cycles per time period than at any other setting. Sure, the engines are air cooled but it's passive cooling, not some kind of active cooling with an engine-driven fan that achieves maximum efficiency at higher speeds. What am I missing here?


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## skutflut (Oct 16, 2015)

JD in NJ said:


> Scot,
> 
> I don't think I understand you on point 1. At max throttle I would think they should be generating the most heat, seeing as there are more ignition cycles per time period than at any other setting. Sure, the engines are air cooled but it's passive cooling, not some kind of active cooling with an engine-driven fan that achieves maximum efficiency at higher speeds. What am I missing here?



There is actually a fan on the flywheel that move air through the shrouds around the engine fins, so its not exactly passive cooling. I put a throttle on my B&S engine a couple of years ago so that I could start it and warm it up gently, rather than 0-3600 rpm dead cold. That's just a personal preference knowing that an aluminum cylinder wall is way softer than a cast iron liner. I also slow the engine down after blowing while I sweep off the snow before parking it in the garage. 

I agree that you need to run the engine full speed when working because the speed of the impeller is what moves the snow up and out the chute. Run it slow, and it will clog, and probably bog down since you are not using that horsepower and torque you paid for.


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## sscotsman (Dec 8, 2010)

fredct said:


> Scot, only thing you said that the manual
> directly disagrees with is #1. It says to move it to full throttle (and full choke) before starting (I'm 99% sure... I'm heading to bed and I don't have the manual in front of me but I'll double check in the morning). Do you feel strongly enough about that that I should ignore the manual there?


different engines have different starting positions..
on my 1971 Ariens the "start" position on the throttle label plate is about 75% of full speed.
Im not surprised that many newer engine have start set at full-throttle..
I dont know that it matters much either way.

I have always read that it's better to start slightly slower, not at full throttle, because you want to give it a few seconds for oil to get working lubricating the cylinders, and slower is better than faster for that process..but its likely a wash either way.

If in doubt, do what the manual says! 

Scot


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## sscotsman (Dec 8, 2010)

JD in NJ said:


> Scot,
> 
> I don't think I understand you on point 1. At max throttle I would think they should be generating the most heat, seeing as there are more ignition cycles per time period than at any other setting. Sure, the engines are air cooled but it's passive cooling, not some kind of active cooling with an engine-driven fan that achieves maximum efficiency at higher speeds. What am I missing here?


yep, as skut already said, there actually is "active cooling with an engine-driven fan that achieves maximum efficiency at higher speeds"
the fan is part of the flywheel.

Scot


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## JD in NJ (Dec 21, 2016)

Thanks guys, I never thought about the flywheel acting as a fan, just those cooling fins sitting out in the air.


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## rkchainsaw (Jan 2, 2017)

I agree with Scotsman on all of his posts. My theory on running it slower is making the engine work(lugging) will cause it to heat up quicker. And with the RPM's slower, the flywheel fan is not moving enough air for the full cooling effect.


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## Kielbasa (Dec 21, 2013)

I always run my machine with full throttle. Simply because I need the best throwing distance just about at all times. 

Now as far as starting my machine, since my repower, I have started her at about half throttle and I raise the throttle as she warms up, for about 2-3 minutes, just to let her warm up. This might not be necessary, but this is how I have been doing it. To me, starting her with full throttle seems like too much force and strain right at once. I might be all wet on this, but this is what I have been doing for the last 5-6 years now.


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## DriverRider (Nov 20, 2016)

Historically small gas engines have been designed to operate between 1800-3600RPM with governors typically set around 3200RPM for most equipment. 3600RPM is used almost exclusively on generators where it is required to get the 60Hz for line AC.

The torque power (TP) ratings found on snowblowers of today are all done at 2600RPM per the SAE standard. If the engine manufacturers are all doing their dyno testing at 2600RPM it should tell you something that it will not self destruct or is harmful.

Select an RPM which gives you the throwing distance needed combined with desired walking speed and snow conditions without lugging the engine.


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## mrfixit (Dec 3, 2016)

I believe that lugging an engine is the most harmful way to use it. 
Lugging puts more stress on engine components IMO. Mainly rod bearings and probably piston pins.

As mentioned causes more heat too. 

I will add this, maybe stretching it some but.
A vehicle with an auto trans has set shift points, it prevents engine lugging IMO. 

My truck has a tow mode that changes the shift points to a higher RPM to keep it in the power band instead of lugging it.

My 2 Cents.


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## all3939 (Dec 21, 2014)

fredct said:


> I just bought my first snow blower and got it set up. Reading the instructions I had a couple questions, including what should in done when the instructions say "set the throttle to the desired setting". I'm, okay, but what if I don't know what I do or should desire??
> 
> I googled around but didn't find much info. What I did find had people generally saying they ran wide open/fast. But when I called with my few questions the rep answered most satisfactorily... except that one. For that I was told I should be run it at slow. Butdidn't get much of an explanation as far as the pros and cons.
> 
> I always like to make an informed decision so I turn to you... what benefits do I get from running fast vs slow? Does fast literally move it (turn the wheels) faster? More power to the auger and impeller? What difference would I see? What's the benefit to running slower? Less wear in the engine? Lower gas consumption? What?


Fred,
Most of the members here offered opinions on the start and run throttle positions. You also alluded to wheels... WOT should always be the rule when using equipment the way they're meant to be used. The auger and impeller speed are optimum at full throttle. Your wheel question.... Gets decided with the speed selection. That controls the travel speed regardless even at WOT. When snowblowing always use WOT and depending on the snow amount and snow quality, then you select the speed. Lower amounts of snow need faster travel speeds to keep feeding the bucket with a continuous feed to the impeller and getting a good throw. Bigger snow fall amounts need slower travel with the same results. When you get familiar with your equipment you'll be your own judge on how much it will handle.


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## Normex (Feb 21, 2014)

Just would like to add that many new snow blowers don't even have a throttle which makes it full throttle from start to finish and I have no qualm with this but as an added protection I use synthetic oil that provides a long lasting film on the cylinders. 
The engineers have spoken with this new approach or the bean counters take your pick.
Fredct there are endless discussions here on this topic but in the end most will say to follow your manual.

Good Luck

Norm


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