Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

I apologize if this is an elementary question but I am a new homeowner and do not have alot of knowledge on engines in general.

I have a 1/4 acre lot and plan to do my own lawn maintenance. I've already purchased my mower and am now looking at getting a trimmer.

I've noticied the big difference in gas-powered trimmers seems to be 2-cycle or a 4-cycle engine but I'm not clear what the pros and cons are of each. Also in some of my research I see that some units take straight gas whereas others require a mixture. I'm just completely confused at this point at what to even start looking for. I dont have a large lot that requires a tremendous amount of trimming but I want to purchase a unit that will be durable and most fit my needs. Maybe my needs would be better suited with an electric model?

Any explanations and advice would be greatly appreciated.

Rob thanks for the post,  and I am in a little hurry here, so I could come off wrong.    Now I am not kidding when I said thank you.  But I have a disagreement with you saying modern 2 cycle engines have mechanical valves, and we are talking in the internal combustion area, as my original point is they are prone to burn out there on small ope engines, like string trimmers etc. 

The engine you posted and used as an example is not a two cycle engine. It is a hybrid.   It isn't even close to a 2 cycle. it uses a 4 stroke cycle which needs mechanical valves in the combustion area..

Stihl is one of the new kids on the block with it, so I will post their info admitting it is a 4 stroke.

I have never seen any 2 cycle engine with any internal mechanical valve in the combustion area. (maybe that don't mean there are none so feel free to show me, I'm here to learn)) .  The reed valve is a trap door check valve, sometimes called a flapper valve , flow direction valve, whatever. It is normally between the carburetor and the crankcase of the engine,  In short no where near the internal combustion area.  on some two cycles it is actually incorporated in the carborator.  Certainly wouldn't want any combustion or excessive heat in there. 

The engine you are describing and posting a picture of is called a Hybrid 4 mix.  It is not a 2 cycle engine.  It is a 4 cycle engine with oil mixed in with it's gas, as they are trying to duplicate the lubrication system (and only the lubrication system)  of a reliable 2 cycle, because 2 cycles are able to run upside down and still lube themselves. I will see if I can past  in Stihl's  drawings and explanation of it.  They clearly state it is a 4 cycle engine.  That's why it has valves in the internal combustion area.  What the crazy EPA is  having these guys try  to invent  is a  substitute for the mighty and maintenance free 2 cycle, and they have went as far as throwing oil in the gasoline of a 4 cycle "Otto" engine. I only mentioned the inventor cause I wanted to say he gotta be rollin around in his grave over this. 

     All kidding aside,  I like those young engineers experimenting,  because someday they may come up with something better..It is possible.   But if they do it ain't going to be in fine print at the bottom of an advertisement.  It will be on the front page of Fortune Magazine,  and naturally it will also be so complicated and un-affordable the whole article will be, them telling us how not to worry cause we really won't have to pay for it.  etc etc. 

Here's Stihl's explanation   http://www.popsci.com/popsci/bown/2003/article/0,18881,537079,00.html

Illustration by Garry Marshall

Two-stroke engines (1) have two main benefits: They have a high power-to-weight ratio, and they can be run upside down. Yet these perks come at a price: The two-stroke configuration is valveless, and some of its unburnt fuel leaks out as exhaust. Four-stroke engines (2), though not as powerful, have a valve on the exhaust, so they are cleaner. The crankshaft is lubricated with oil in a pan, however, so they cannot be turned upside down. A two-stroke gets around this by using an oil-gas mixture for both fuel and lubrication. (3) The Stihl 4-Mix Engine takes the best parts of both engines. It uses a four-stroke cycle, so exhaust valves prevent the escape of unburnt fuel, yet its gas-oil mixture lubricates the crankshaft the way a two-stroke does, so the engine can be oriented in any direction. As the crankshaft turns, it sucks lubricating fuel into the crankcase. This keeps the entire crankshaft lubricated even when the engine is upside down.   The real problem I have with their advertisment, is how can they claim they can ever hope to get more power in the same size 4-cycle.  When all they are doing is altering the lubrication system,  (sry but getting rid of a conventional splash system just won't even come close)  My guess would be some of the same horsepower lies we have investigated in other threads, as in using horsepower in and over operating range  etc.  Who knows maybe they are talking at idle speed.  It could be true there.  What good it will do there is beyond me.   Anyhow call it up, some interesting pictures of the different styles of engines. And remember their claim of more power in the same size engine is in fine print at the bottom of the article..Sure ain't the new york times. Ben07

 

snowshoveler wrote:

Hey Chris..........................

Please don't think I'm trying to steal any thunder from you, here.   I do bow to you the professional technican!  I have a landscape maintenance company that has been in business since 1988.  I am definately an end user and not a tech., but with countless hours of use "under my belt", I know what works and what doesn't.  I've tried them all.  I can only extend the knowledge that if something stands up to commercial use, then it will likely be a lifetime purchase to homeowner use.  And, that, is money saved in the long run. 

I think that one of the greatest things about this site is the fact that all the knowledge shared results in wiser spending of our hard earned dollars by "crying once" and buying better quality OPE. 

Ken

I think I really only had two points from the beginning.

Two stroke engines have changed a lot in the last couple of years from what most of us are used to, in order to comply to EPA standards here in the US.

Even old time two stroke engines have valves, called reed valves that can fail and cause the machine to run poorly or not at all. And they do fail from time to time.

robmints wrote:

I remember my dad saying that the reed valves would get weak from "flapping" all the time and would usually be the cause of poorly running machines (usually Lawnboys) that would come into the shop.  I've worn out a few myself from back in the day when we ran Lawnboys exclusively.

Ken

Great in-action working model of a 2 cycle
http://www.oldengineshed.com/twocycthry.html

well folks the still 4mix is a carbon copy of shindiawas 4 stroke unit and neither one is much good.we sold the shindiawa 4 stroke units and after i get done doing all the recalls and updates ill be an old man.

i really hate it when a company brings out somthing and claims its te best thing since sliced bread,then we find out it went mouldy and has to come back in for repairs .

eventually they will bring in fuel injection and that will be the end of 4 strokes.

now i know some of you are saying no way but what if i tell you that your precious 4 stroke isnt so clean after all and the only reason they build them at all is so they can earn credits to play off on their not so clean units.

did you know that fuel injected  2 strokes have been tested to run at a mix equal to 400 to 1. they are variable ratio oil injected ...changes with load and rpm.

its complicated now but getting better all the time.

a fuel injection 2 stroke can run cleaner than almost every 4 stroke.

dont beleive me check out a mercury outboard called OPTIMAX...awsome engineering in that thing and cleaner than any other 4 stroke outboard.

i like 4 strokes but they have not earned their place in small hand held ope yet.

later chris

Chris,
What about Echo's Tornado power, or what ever they call it.

echo is top quality product (used to sell it) but you could look at a srm 2300 or 2500 and have a very nice machine  that will last a lifetime with little or no maintenence.

i feel that the 4 stroke are gonna be a problem after a couple of years ,especially if they dont get used much.

just check out the price of a carb kit for any 4 stroke trimmer and maybe a spark plug ...if you can find one ,and you wont fine one at walmart.

if you leave you gas get stale once its gonna be very costly,i end up replacing every second carb on the 4strokes if you even mention bad gas around one of them.

and that just makes them impractical to me.

stale gas is a way of life we all do it from time to time and  sure its anoying ,but with these ones your gonna pay through the nose

.buttlint ...how much does a carb lit cost for one of your stihl 4 strokes and how many do you have in stock...the kit i mean not the trimmer.

later chris

Well, SnowShoveler has pretty much convinced me to go with a 2 cycle trimmer.

I had been considering the Honda units, but had some concerns.  I am leaning towards the Echo 230 or possibly the PAS-260 for some flexibility with trimmer, edger attachments.  Though some say that the you should't use the PAS model for your primary edger.  I guess my question is - if you should not use it as your primary edger, what is the point?   Are you better off with a dedicated edger?

Also, liked a Husky model I saw - 326.

Not as primary edger? Bullsnot.

Mine works fine, has for years. Bottom line is, once you have a nice groove, it doesn't take much at all, you'll fly down it.