2 cycle vs. 4 cycle weed eater


Old 11-17-04, 10:19 AM
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Question 2 cycle vs. 4 cycle weed eater

I just bought the 4 cycle straight shaft craftsman and it seems like it does not operate as good as the 2 cylces do. I think it (the 4 cycle) turns at less rpm's and I am not used to this. Did I buy the better or should I return it for a 2 cycle? I have to give the 4 cycle alot of gas for it to turn and cut anything.
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Old 11-17-04, 10:37 AM
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A 4 stroke hits its power band at a lower rpm than a 2 stroke. The 2 stroke will rev and recover from overloading quicker, while the 4 stroke should be harder to lug down even at lower rpm.
You may need to alter how you use it a bit depending on what you use it on also. 4 stroke will run quieter with less emisions and last longer with proper upkeep.
If you use quick sweeps pausing at the end of each with the 2 stroke, try a bit slower but more constant sweep.
Old 11-17-04, 04:32 PM
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Good advice... I would also add that these trimmers are for light duty, so, don't take them into deep grass like field grass or brush, or your new trimmer will not last very long.
Old 11-17-04, 07:23 PM
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A two cycle engine will typically have a lot more horsepower for the same weight than a four cycle one. Since there is no need for an oil sump in a two stroke, it would be physically smaller as well. In fact, I can think of no over riding reason to use a four cycle engine in such an application. Perhaps it was deemed that the two cycle emitted too much pollution. I know in California there was some concern over the pollution from outdoor grilling and from lawn mowers so I guess that trimmers could get hit with the same stick. For my money you can't beat a two cycle when the application requires high power in a small package that will operate at odd ball angles. Sure, for the most part they are throw away engines, but for the same reasons equivalent four cycle engines would be too.
Old 11-18-04, 09:52 AM
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I would agree Jug especially in this application, I do think tho it is "Emission" driven and expect to see much more of it in the near future. I ride Dirt Bikes, and the manufactures have been R&D themselves to death to make 4 stroke engines competitive with 2 strokers and have accomplished that feat in the motorcross/supercross circuits. I am pretty sure the government has a date set for them to meet a certain criteria. I know these things do seem to originate in California, (which I do NOT reside in) however I am on the west coast so perhaps it bleeds over here a bit sooner
Old 11-18-04, 11:08 AM
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California State Law mandates that all 2cycle equipment must be run with a catalic converter installed. Go check it out. Even Stihl mentions it in there product manual. If I wanted to run my new Stihl trimmer in California, I would have to install a catalic converter.
Old 04-01-10, 11:58 PM
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2 Cycle Vs. 4 Cycle

I have a $250.00 4 Cycle Troy Built that is two years old and has been used probably 10 times. I also have a low end 2 Cycle that cost much less, is 8 years old and runs like new, have not had any problems with it. The 4 Cycle is locked up to where the pully crank will not pull and I am going to have to try to find out if the cord is tangled or if what I was told, if it is not the cord, then it could be a costly fix.

I thought that using a 4 Cycle would be a better performer, more power, more reliable, and a would be a good investment in doing lawn work. But instead I think the only sells point for the higher priced weed eater is that is pollutes less, but it uses more gas...so I don't see it really helping the environment. It is heavier, requires more care, and I am moving back to using the 2 cycle.

I have searched the internet to find 2 cycle vs. 4 cycle and most everyon who has used both, says the 2 cycle is much better and it is cost less. I feel mislead in the purchase of the 4 cycle and in lawn equipment I have found that just because it cost more, does not mean it is better. Just like Lawn Mowers, the majority use Briggs and Stritton that are the work horses of the mower world and I have seen a low cost Craftsman last nearly 18 years with a Briggs and Stritton and then I see all the other mowers from $300-$700 with the same engine company, just a different name.

So if it comes to weed eaters, I say 2 cycle and lawn mowers are good as long as they are powered by Briggs and Stitton.
Old 08-02-10, 04:02 PM
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2 stroke vs 4 stroke

a four stroke engine is not defined as gas and oil seperate. it is determined by the fact that the piston goes up and down four times per spark. many competitor trimmers are a four stroke and what i have heard is that they are not all position trimmers. stihl has four strokes that require two-cycle mix. the common misconception is that they are there for two stroke engines. so for any one purchasing a trimmer should check and make sure what you are getting is an all position trimmer (many customers i get use their trimmers to edge).

On another note, four stokes have more power and torqe than a two stroke of equal size and weight. they also burn less fuel (even with the two cycle mix). Much of what has to do with changing from two to four is to do with emission regulations from the EPA. if anyone has bothered to purchase a new gas can you know how much of a pain it is now with simply using it.
Old 08-02-10, 09:04 PM
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Well, actually a 4-stroke is named such because the engine goes through 4 strokes in order to complete one complete cycle from fuel introduction to exhaustion. It takes 2 revolutions of the engine (2 times the piston going up and down) to do this, and it sparks every revolution, regardless of the stroke, on most all 4-stroke engines, be it small engines or automotive engines.

A 2-stroke engine completes it's cycle in one revolution of the engine (piston goes up and down once). It hits and produces power every single revolution instead of every other like a 4 stroke.

2-strokes have more power, not 4 strokes, in general, especially when they are equal size and weight. A 2 stroke can do what a 4 stroke can do, but with less weight and size. They are generally not as environmentally friendly, however, there have been great improvements in 2-stroke design with exhaust scavenging, catalysts, and other innovations that make some 2-strokes run even cleaner than many of the 4-strokes out there.

Hopefully they will continue to improve the efficiency of the 2-stroke so that we can continue to get the benefit of the lighter weight with more power that a 2-stroke affords us.
Old 08-03-10, 03:31 AM
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fwiw, my experience with people buying a 4-cycle line trimmer had absolutely no concern for power:weight, the idea of not having to mix oil with gas was the appeal that sold them.
These same people never think about checking the valve adjustment and never check the little oil reservoir.

I've only repaired and used a Ryobi and a TB, looked identical except for color, they seem to be fairly rugged units, but like any, they run best with fresh gas and good fuel lines and filters.
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