Lawn Mower efficiency- Miles to the gallon

[wooferhound]

So I'm mowing the grass at my house today and thinking too much. I just bought a new Lawn Mower and I'm getting a lot more of my yard cut using the same quart (.95 liter) of gas. and having the enquiring mind that I do, I was wondering . . .

Do they care how efficient the Mowers are when they design them ?

How can a person determine how many miles of grass they can cut with a mower, or

How can you compare efficiency between brands and models ?

How many flowers do you kill when you cut the grass ?



W o o f -={(

[valterra]

I don't know much about engines, but I imagine just the sheer difference in weight between an auto and lawn mower much more efficient.

Can you imagine seeing x/city x/hwy stickers on

lawnmowers?

Darn it woof!  Now you've got my brain going too!

[jonas302]

I do believe they fall under epa regs so probly have improved in gallons per hour or however you can measure it  I have noticed less comsuption  on some of my equipment to

[commanda]

Shame on the lot of you.

I use an electric lawnmower and have moved all my pollution to my local coal-fired pollution generator :-)

Seriously though, I believe the coal-fired power station is orders of magnitude cleaner and more efficient than my old 2 stroke lawn mower. Electric works great for a small suburban yard.

Amanda

[tecker]

Don't mow your lawn turn it into a garden and harvest it .  I know this sounds naive but still still better than the Saturday mower event .

[tecker]

Uh oh I can hear it now " the next thing that kook wwwwwwill be talking about free energy from hot air " .

[Stonebrain]

What about this model?

Anyway I think grass mowing is burning energy just for making a surface inproductif.

If you can't make it productive with sheep(or rabbits) Reduce the surface of the grass so you can do it with a handmower(yes that exists!).And make the bigger surfaces productive with trees.

just my point of view

cheers,

Jaap

[ghurd]

My old mower, 3rd hand, circa 1985, was well maintained and burned almost no oil.

I changed it every other year, but never had to add any.

It took a hair (like a spoonfull) under a quart to cut once.

Rock solid, easy to start, 4HP B&S.

My 'new' mower, 2nd hand, circa 2003, was abused for a short time and burns oil.

It holds more than a quart (1.5?), but I can cut 5 times with gas left over. Maybe 6 times.  It is hard enough to start I don't push it to the end.

Fairly lame, hard to start, 6.5HP Techumsa.

Huge difference.

G-

[BigBreaker]

Catalytic converters require an air/fuel mixture slightly above the stochiometric ratio, so regulated, catcon'd engines run rich.  Movers and chainsaws can be run lean and more efficent, but at the cost of NOx, HC and other emissions.  Two cycle engines run with oil in the fuel too.  That's not especially helpful for emissions.

[DanG]

Razor sharp & balanced blade  ● synthetic oil ● clean air filter ● proper plug and gap ● 2-stroke ports carbon-free ● run engine at low end of power band ● shut it off instead of idling ● keep moving forward instead of fifty U-Turns ● get soil analyzed and add only needed amendments not the sexily packaged high Nitrogen fertilizers ● clean underneath your lawn mower's deck often to reduce resistance...

[Bruce S]

Like Amanda mine get 1000 miles to the gallon. I use an electric. Was a plugin one , now battery powered and solar recharged.:-)with my new powerhouse :-)

Look under "hood" follow incoming AC to recifier or to motor. AC oh-well. Rectifier, then motor is 12Vdc, remove recitifier and run off batts.

I'm lazy, gas motor shakes my beer, electric line trips dog.

Cheers

Bruce S

[Jon Miller]

My dad has a 4 stroke strimmer (weed basher) made by honda and it uses about 1/10th of the fuel his 2 stroke one does.  My dad is a gardener for a living and believes hes using about a 3rd of the fuel now then when he started 10 years ago.

with regards MPG not sure how to do that.

some thoughts...

[JamesJackson]

Since I do not have any input to the 'how many mpg' question - perhaps I should remain quiet.

I use an electric mower (Black & Decker CM2000?) - have for about 5 years now. Still on the original 24-volt battery (who makes 24-volt SLA's?).

I need to sharpen the blade... but other than that, it runs great - for the small area that I need to mow. The charge lasts about 45-minutes - if that helps.

Regards,

James Jackson

[Chagrin]

P.S. If you want an exercise in futility, google for "lawnmower efficiency". The first hit? This page.

[Norm]

This is one of the key factors ...quite a while

back I used an oil additive that was claimed

 to have Teflon in it. When I used it ...after

one mowing session, on the next time

I had to readjust the idle speed of the carb....

the engine was running too fast. So my theory

was it had reduced the friction....

it always seemed to run a lot quieter after that,

 and it used less gas.

' If it don't start on the second  

pull....somethings wrong '

....a recoil starter could last a lifetime and

no engine 8hp or under should ever need an

electric starter.

[TomW]

Norm;

You know how much I like to argue with you!

....a recoil starter could last a lifetime and

no engine 8hp or under should ever need an

electric starter.

I bet you never had to start your wood splitter below freezing with an 8 horse briggs on it, have you?

Otherwise you would retract that no electric start needed statement when you get up around 8 horse.

I use a spritz of ether then, too. Either that or park it in the sun awhile and pray.

Just poking you, ole buddy.

Tom

[Jeff]

I would love to have an electric to cut my lawn! I do have about 1/2 acre that I keep mowed now (sort of). I can't keep up, but I try. I've survived on a couple of hand-me-downs the last 5-6 years, push mowers with a 3-4hp motor on them. A couple of friends helped me adapt them to attach to my wheelchair and whaalaaa! instant "riding mower". My current/best one is a two-stroke Lawnboy (yes, you mix oil with the gas). I use a 12oz. glass to mix the gas & oil, and go to it with that. Sometimes I can get most of it mowed before it uses it up. I do have a weedeater I made from a 12v fan motor out of a car heater, works great! It even has the fancy "bop-it-on-the-ground" thingy to reel out more string! I just plug it into one of the batteries on my wheelchair!

[kurt]

ever had to start your 5.5hp snow blower when it is 10f or under out if you ever do you will be praying it has 120v electric start on it like the new ones do..... most of the time you don't need it one or two pulls and your off but when its really cold you really need it or you will be pulling and cussing all day...

[Norm]

No I never I never had trouble starting my uncle's

wood splitter....a real nice long handled axe and

heaven help you if you ever broke the handle!

   Besides....Why would you wait till it's below

freezing to split wood ?

   You can probably top me on this one but thanks

for the humour.

  (Norm walks away muttering aomething about

wimps and their log splitters)

[Norm]

Is your 5.5hp snow blower a Briggs?  Tecumsehs are harder to turn over in cold weather.

[kurt]

ya its a briggs pops over fine when it is warmer but when the real cold rolls in after it snows you need the electric start...

[vawtman]

Hi Norm

 I'm running amsoil in my 9.5 techumseh blower and never had to pull it more than once all winter to start it.Guessing around 20 storms.It has estart but i'm too lazy to plug it in.

 Got rid of my snowplow on the truck i can do the job faster with the blower and turn into an abonible snowman at times.Its fun and at half the fuel and wear and tear.

 Mark

[elvin1949]

Hi Norm

  It is wood getting time right now.Plan on having all my wood cut and split before i go to my daughter's in July for her birthday.

  Getting to old to split it with an axe.I use a

6lb sledge and wedges now.

 later

Elvin

[Bruce S]

McG;

  That's making good use of items at hand!!

There was something similar on the Scinece channel. They took an electric mower and attached it to a bicycle. Worked pretty well. Is your chair's battery setup expandable?

Cheers

Bruce S

[Norm]

You're getting old? Me too ! Haven't burned wood

since then back in'45.

 Ah good ol sledges....

[GeorgeMo]

I was wondering about this too. I'm curious about how much energy a gasoline lawnmower wastes and how to calculate that.

Looking at it from the input side, it seems that the "fuel" cost of operating a gas mower and an electric mower is about a wash. Each gallon of low octane gasoline has about 36 Kilowatts of power in it (according to the Energy Information Administration's numbers). A gallon of diesel has slightly more power - equivalent to about 40 Kilowatts.

With electricity north of 10 cents per Kw and gas at around $4 per gallon, those work out to about the same. Of course, if 99% of the energy in the gas is wasted as noise, heat, and idling, then that changes things.

Anybody have an idea about how to calculate the waste energy in a gas mower?

[Jeff]

hehe...I couldn't start a 25cc weedeater with a recoil start!

[Jeff]

re: "McG;

  That's making good use of items at hand!!

There was something similar on the Science channel. They took an electric mower and attached it to a bicycle. Worked pretty well. Is your chair's battery setup expandable?

Cheers

Bruce S"

It is now! It came with two 34amp/hour sealed gels, and I have added two recycled 50amp/hour gels just because I do my lawn with the chair. I have two plug-ins for the weedeater to help distribute the load. Wish I could do enough work to start setting up more folks in power chairs with things like this, I think there would be a pretty good market for it!

[GeorgeMo]

I found this information about engine efficiency in automobiles:

"The calculations are extremely complex, and include variations depending on water flow rates and cooling system design, but they generally indicate that a conventional internal combustion engine cannot have an overall efficiency of greater than around the low 30% range. As noted below, there have been some experimental engines designed that have been measured at around 28%, but the most efficient production engines are around 25% and most vehicles on the highways now have engines which have around 21% overall efficiency."

I would presume that lawn mowers have even less efficiency (due to poor cooling systems, lack of exhaust gas recycling, and increased energy loss to inertial factors). Does anyone have an idea how to quantify that though?

[2dumb2kwit]

 Norm,

You make a good point. DanG nailed it, but you are corrcet about the oil.

Todays oil has little, or no, zinc. Zinc was the biggest friction fighter in oils of the past. Some oils, meant for diesels, still have some zinc in them.(Different EPA regs, I'm told.) Regular motor oils are not the best option for small engines, like Briggs.(They use flat-tappet cams, etc.)

 Synthetic oils are slickerer,(Thats a technical term.)and of course additives, like you're talking about, will reduce friction.(Thats almost like free power!)

With synthetic oils, you can also use a lighter oil and have the same protection.

 I have seen the difference between oils, in racing engines on the dyno.

I have seen changing oil (still the same weight oil) gain 7HP. Going to a lighter weight is another small gain.

 OK, I've rambled enough. I'm not even gonna start talking about fuel atomization.

 Later guys.