Gas-powered or Electric-powered (cord-free) weed wacker…which is better? I have Googled and read the gas will need more maintenance; however, the gas is lighter, the gas is typically more powerful, and the gas will last longer*. Your thoughts?
*This may only be true of commercial models built to take a beating.
Oh, I should have added: Which is better? Straight or curved shaft?
Heavy use, large yard: gas.
Moderate use: high quality cordless.
Light use, smaller yard: good quality cordless or corded electric.
We have a near-commercial grade Toro gas one that unfortunately sat for several years and needs a more delicate carb rebuild than I am good at, so until I get it over to the small engine shop in town I bought an electric at Harbor Freight Tools - $29 shelf, $25 out the door with their 20% coupon. It’s very well made for the price, and has worked flawlessly so far. When it craps out, I’ll junk it without a regret.
But what I’d really like is a high-end cordless. Too expensive with the Toro sitting there needing minor repairs. 
Adjustable head position is a huge asset. The HFT one has it. Most good ones do as well.
Ok, so here’s what you have to choose between :
Gas - no dragging a heavy cord around. However, every time I fire mine up, I have to adjust the choke just right or it won’t start at all. I have to pull on the cord about 20 times on average. Depends on how fresh the gas is. Every time I try to start it, I know that this might be it, and the engine might not start at all this time. (and I would be forced to take apart the engine which is composed of many, many small parts and you need to have the right kind of wrenches handy, and little “tricks” are required to put the parts back together at all)
Electric - Is the cord plugged in? Then it’s virtually guaranteed to work. The electric ones die eventually but until then, they pretty much work and work and work. However, dragging that heavy cord around is a real pain, and you then have to wind the cord up every time, and unwind it next time, and those cord winder/unwinder things tend to cause even more trouble than they are worth. Other drawbacks of the electric - the motor is often in the lower part, near the head. That means it’s unbalanced to carry and use and uncomfortable to use for prolonged period. Eventually, you’ll accidentally mow your cord or something and sometimes see a dramatic flash and then a breaker will blow. If you’re like my folks, you’ll repair the cut cord somewhat shoddily and now you have an electrocution hazard to worry about next time you go out.
Cordless/battery - sort of a hybrid. The batteries age quickly on all appliances like this, so after a few years you may not have enough battery life to do your whole lawn. Eventually the battery will be what fails. However, until then, it will probably work first time every time, and you can just buy a new battery whenever it quits.
Weedwackers and leaf blowers are primarily for tormenting your neighbors. Choose based on volume and how much you hate people.
I like my electric. I can get 90% of my yard with the extension cord. For the rest, I have a battery powered one. But I hate that one. It has much lower power and the autofeed only spins out line when it’s first powered up. When the line gets worn down, which happens quickly, I have to flip it off-on-off-on… until it has more line. (It’s a Ryobi). My electric has continuous feed, which means I can do long, continuous runs.
Unless I knew how well it worked, I would not get a battery powered one. If the power’s too low, it may not be able to cut an edge or cut through tough weeds. And they may make compromises to save power (autofeed) that affect performance.
Straight shaft, FOUR CYCLE. A quick change split shaft is nice too for multiple attachments.
We have Troybilt and Toro trimmers with nearly identical engines that work great and use the same gas as the lawn mower with no mixing. A straight shaft is nice to get under bushes and seems more heavy duty.
The same way you can just have that nice Porsche 944’s engine rebuilt. 
Unless you invest in a whole line of tools that use the same battery, I’ve found that a battery crapping out means the tool is EOL. I’ve had a succession of cordless drill/drivers over the years, and every time, when the second battery gets sketchy, it’s a far better move to buy a new unit with two new batteries than replacements for the old one. It seems like most smaller battery tools are thrown in free with the purchase of the batteries. And there’s no good alternative; I’ve looked into rebuilding the battery packs and even at online prices, the NiCAD or Li-Ion cells are about the same as a good price on a new battery.
I suppose a very high-quality tool is worth buying a new battery for after a few years. I haven’t encountered that case yet, and I am both a tool maven and a frugal bastard.
I have a curved shaft Stihl electric. I know the pros want gas and a straight shaft, but this thing is a beast, and I don’t really whack grass as much as rocks. My desert landscape still has grass coming up thru the river rock and I just go down there and beat the hell out of the Stihl and it keeps ticking. I think it was around $150 and I’ve replaced it once in 10 years. A new head (around $25) every couple of years–which I wouldn’t need but for the rocks.
Tell me about two-cycle vs. four cycle. I understand the mechanical differences. Is the gas-oil mix for a two-cycle more expensive and harder to find since you can’t run to the corner gas station? Is that why you’d recommend a four stroke?
Two-strokes are lighter, simpler and can be more durable, but require “mix” fuel with 1:50 or so oil. It’s not hard to dump an ounce of oil into a small gas can, but you can use ONLY that fuel (never regular gas), and it’s not good to use “mix” in regular engines. So you have the hassle of two gas cans, one of which doesn’t get used very fast.
Four strokes have improved a lot but are still usually heavier and a bit fussier to maintain. They can use regular gas like your mower. The commercial ones are much more durable than two-strokes and most consumer four-strokes.
Neither one will start easily if it’s out of tune or needing maintenance. Opinions differ on which one is ‘better’ in that respect.
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Is the gas-oil mix for a two-cycle more expensive and harder to find since you can’t run to the corner gas station? Is that why you’d recommend a four stroke?
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It’s slightly more expensive just because you need to add 2-stroke oil to the gas. It’s also a pain in the butt because you have to add oil to the gas, so you need two gas cans - one for the lawn mower’s straight gas and one for mixed. If you don’t fancy the idea of playing fuel chemist, you can buy pre-mixed fuel, but at a rather stiff premium of around $6-8 per quart.
Also, some states (California jumps to mind) have been trying to phase out or even ban 2-stroke engines because their emissions are typically worse than a similarly sized 4-stroke.
For my yard, I have a corded electric mower and a battery-powered trimmer. Both are more than adequate for my small yard, and I don’t have to worry about oil changes, spark plugs, gummed up carburetors, or even the damages caused by the E15 regular gas sold here. Ethanol is not good for small engines.
If you don’t know how to rebuild small engines, get an electric one. I guess the corded ones are the can’t go wrong option. Look for a corded electric one with the motor in the rear so it’s balanced to carry. Get a really long cord. At least it’ll work, and keep working.
As for 2 cycle gas in a 4 cycle engine - I got low on mower gas and tried it. Works fine.
Consider: Your wife or teenager calls you at work, "I need to weedeat, do I use the gas out of the big can? :eek: “Oh! It’s gas AND oil, how do I mix it??” :eek::eek:
I don’t worry or fuss with that anymore. And it took me from 4 “gas cans” to 3.
or +4) 32/1 for most 2-stroke weedeaters (unless you buy a $350+ Stihl weedeater)
Although it’s not great practice the 50/1 can be used in a 4-stroke engine with no smoke - I have to rescue my riding mower using chainsaw mix at least once a month.
A 2-smoke does have a higher power/weight ratio than a 4-stroke and that’s important when you’re racing motocross or lifting a chainsaw. The quality of engine construction seems similar between the two designs.
This is similar to my trimmers: http://www.lowes.com/pd_372989-65481-TB6044+XP_1z0wgb2__?productId=50146118&pl=1
4 stroke engines tend to be heavier–heft a Honda 4-stroke trimmer and a Stihl or Echo or some such 2 stroke and compare. gotpasswords is right on the money about ethanol–it’s a real problem for today’s 2-stroke engines. Stihl makes a product called Moto-Mix that is highly recommended for 2-stroke handhelds. It’s not that expensive vs. having to take a tool into get it de-gunked–if a gas-powered tool with over, I think 8% ethanol/gas mix, sits for say a month, you got trouble.
I had two gas trimmers, a Stihl FS85 straight shaft and a Ryobi straight shaft convertible. I keep a steel blade on the Stihl for heavy weeds and small trees. I use the Ryobi for trimming grass. Actually I used to use the Ryobi but don’t anymore because I bought a Echo battery electric for trimming grass. It has a 5 year consumer warranty. Just pick it up and go trim grass. It seems to have lots of power with its LiIon battery pack. I love it.
We have both a gas and a corded. The gas is a 5 horse on large wheels with a 21" cut. Standard lawn mower engine. Works great for trees, fences, and steep ditches. Also for finding baseballs knocked into the next door meadow. Have a long heavy weight cord to reach the vicinity where the corded one is used, then add a shorter lighter cord for mobility. I tie off on belt loop so tool and hands are not doing the pulling, my hips are.