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Bringing this up just for the hell of it : looking over some old posts , and came across this quote : " Your average 4 stroke motor was rated at 500 engine hours, were the 2 stroke motors were rated at 200-250 engine hours of life expectancy before requiring major repair " I`m a big 2 cycle fan . I had a Toro mower with Suzuki motor , from 1989 until 2011 , 5/8 acre , 70 -75 minutes each time . Averaging 26 per season , I figure around 700 hours , and was still running when I sold . I`m thinking my Duraforce Lawn Boys capable of the same . Any thoughts ?

totally depends on how an engine is used and cared for.

jkp62 said:

Bringing this up just for the hell of it : looking over some old posts , and came across this quote : " Your average 4 stroke motor was rated at 500 engine hours, were the 2 stroke motors were rated at 200-250 engine hours of life expectancy before requiring major repair " I`m a big 2 cycle fan . I had a Toro mower with Suzuki motor , from 1989 until 2011 , 5/8 acre , 70 -75 minutes each time . Averaging 26 per season , I figure around 700 hours , and was still running when I sold . I`m thinking my Duraforce Lawn Boys capable of the same . Any thoughts ?

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It depends, upon a lot of things. How good is the engine to begin with? How is the equipment used and how often? How is the equipment maintained? Sometimes equipment will have a sticker on it with an hour rating. That is how long it is rated to stay within EPA standards. Lucky to get 3-5 years out of a cheap 2-stroke trimmer. Not uncommon for 30-40 year old Stihl chainsaws (2-stroke) to come in the shop.

Two strokes generally get a bad rap because of oil type and oil mixing issues. A quality air cooled two stroke oil is necessary and the ratio is important as well. As background I've flown two stroke powered Ultralight aircraft for over 30 years. The Rotax guys that didn't have oil injection always thought that more oil in the mix was better.....all they did was shorten the time between overhauls, coke up the top of the pistons, fill the exhaust port with carbon, foul the plugs and lock the rings in place. I went with a 100:1 mix for all my engines, not just UL but trimmers, chain saws, blowers, etc., and the plugs all looked like four stroke engines and never needed to be replaced. Rings stayed free, crosshatch was very visible after 800 hours and no decarbonizing was ever needed. The amount of oil is vanishingly small because of the roller and needle bearings in modern two strokes. If this were a really old plain bearing engine you'd need way more oil in the mix than 100:1 could provide.The brand of 100:1 oil is not important as long as it has a good name behind it. The other advantage in my case was full instrumentation for EGT and CHT. Two strokes do not like getting a too lean mixture. In your case it's simply learning to listen to the engine as you screw in the high speed needle to hear it break over from a four stroke to a two stroke. It's a learned skill that isn't magic, just a practiced ear.

Really subjective, since it depends entirely on how the equipment was cared for.

That said, as a lifelong mechanic, my 2-strokes last many times longer than the internet would have you believe. I can tune them by ear (whether it's a chainsaw or string trimmer, or a dirt bike / ATV or my paramotor), and they will all last forever.

I've been trimming my 2.5 acres for 22 years on the same Echo SRM-210 trimmer that has only had 1 carburetor (& fuel lines) and 1 spark plug replacement in that timeframe. I'm not gentle on any of my engines - they're there to get the job done as fast as possible. Around my yard it sees everything from low-RPM, light load trimming to full-throttle, chernobyl-temperature "brushhogging" through foot tall grass in the middle of July. Every time I use it I go through a full tank. Sometimes more. I'd wager it will still have well over 100 PSI compression ice cold.

Everything gets mixed with Amsoil Saber at 100:1, except the paramotor. That gets mixed at 66:1 (that was a number a more experienced instructor said he used for his paramotor school rigs for many years with success down in smoking hot LA, so that's what I've been using).

The paramotor has about 30 hours on it, but during climb out, I regularly nudge 400° cylinder head temps.









Oh, and another 2-stroke I forgot to mention. This one has 7k+ miles on it since a complete overhaul. Still runs like the day I first started it. Starts 3 kicks cold whether it sat for 8 hours or 8 months, and always 1 kick warm.

This one gets Amsoil Dominator since it's oil injected. I feel Saber is a bit too heavy for the injection pump and could cause issues.

I have a 20 year old Stihl line trimmer that works well. Was used heavily on a mountain bike trail building project for 5 years. Now maintains my 3/4 acres and occasionally the HOA common area. It’s been used hard in triple digit temps and has has a carbide table saw blade for trimming saplings and branches…..maybe abused is a better word LOL.

If you buy good quality, it will last. The junk sold in big box stores will not last.

Can't believe what I'm reading concerning the 2 stroke engine. In my extremely humble opinion the 2 cycle came right outta the pit of hell. And to fly using a 2 stroke I would need 4 parashots.

Have to admit my Stihl 026 chainsaw, over 25 years old, still starts on the first to 3rd. pull. The Germans know how to build stuff.

The oil to fuel ratio is critical in a 2 cycle.......and DO NOT leave the fuel mixture in the machine for an extended period.

Had a Ryobi 4cycle weed eater that would cut down a redwood tree. Lasted over 25 years. And, if I treated a human as bad as I treated that weed eater I'd still be in jail.

They are the simplest, lightest, cheapest, and most powerful engines for their size. Zero downsides in my eyes. As a mechanic, I wish everything I owned was a 2-stroke, even the cars and truck! A V8 2-stroke would be an absolute powerhouse.

Smithsonite said:

They are the simplest, lightest, cheapest, and most powerful engines for their size. Zero downsides in my eyes. As a mechanic, I wish everything I owned was a 2-stroke, even the cars and truck! A V8 2-stroke would be an absolute powerhouse.

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You want a Detroit 12v-71T diesel. But if stuck in a V8 then a 8V-71TA or TTA.

srwa said:

Can't believe what I'm reading concerning the 2 stroke engine. In my extremely humble opinion the 2 cycle came right outta the pit of hell. And to fly using a 2 stroke I would need 4 parashots.

Have to admit my Stihl 026 chainsaw, over 25 years old, still starts on the first to 3rd. pull. The Germans know how to build stuff.

The oil to fuel ratio is critical in a 2 cycle.......and DO NOT leave the fuel mixture in the machine for an extended period.

Had a Ryobi 4cycle weed eater that would cut down a redwood tree. Lasted over 25 years. And, if I treated a human as bad as I treated that weed eater I'd still be in jail.

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I have a John Deere chain saw I bought new over 40 years ago. Never drained the fuel or used additive. Starts and runs like new.

RevB said:

Two strokes generally get a bad rap because of oil type and oil mixing issues. A quality air cooled two stroke oil is necessary and the ratio is important as well. As background I've flown two stroke powered Ultralight aircraft for over 30 years. The Rotax guys that didn't have oil injection always thought that more oil in the mix was better.....all they did was shorten the time between overhauls, coke up the top of the pistons, fill the exhaust port with carbon, foul the plugs and lock the rings in place. I went with a 100:1 mix for all my engines, not just UL but trimmers, chain saws, blowers, etc., and the plugs all looked like four stroke engines and never needed to be replaced. Rings stayed free, crosshatch was very visible after 800 hours and no decarbonizing was ever needed. The amount of oil is vanishingly small because of the roller and needle bearings in modern two strokes. If this were a really old plain bearing engine you'd need way more oil in the mix than 100:1 could provide.The brand of 100:1 oil is not important as long as it has a good name behind it. The other advantage in my case was full instrumentation for EGT and CHT. Two strokes do not like getting a too lean mixture. In your case it's simply learning to listen to the engine as you screw in the high speed needle to hear it break over from a four stroke to a two stroke. It's a learned skill that isn't magic, just a practiced ear.

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Two strokes are louder, and smoke. Those are probably the two main reasons that many manufacturers have gotten away from them a lot.

Do not mix oil to fuel at anything except 50:1. You can do your research. You can argue. You can disagree. 50:1 is what is recommended.

If taken care of, two stroke equipment will last many years, especially if it is quality brand to start with.

Tiger Small Engine said:

Two strokes are louder, and smoke. Those are probably the two main reasons that many manufacturers have gotten away from them a lot.

Do not mix oil to fuel at anything except 50:1. You can do your research. You can argue. You can disagree. 50:1 is what is recommended.

If taken care of, two stroke equipment will last many years, especially if it is quality brand to start with.

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And before 50:1 it was 20:1 with plain motor oil, then it went to 25:1, then 30:1 with castor oil, then 40:1 with specially formulated two stroke oil that served both water and air cooled. Then 40:1 with oils specifically formulated for water or air cooled. Then 50:1......and then everything stopped. No more progress. Oils couldn't get any better so they quit. Same for metalurgy and bearings. Everybody just gave up.

mcspeed said:

I have a John Deere chain saw I bought new over 40 years ago. Never drained the fuel or used additive. Starts and runs like new.

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I'm a "touch prejudice" regarding 2 cycles. First "run in" with them was in the late 40's early 50's. Was not a good experience.


I was born in March of 37......1937.............do the math.

Smithsonite said:

As a mechanic, I wish everything I owned was a 2-stroke, even the cars and truck!

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Yeah, but they would get 3 mpg.

I've had good luck with 2-strokes. I raced 2-stroke dirt bikes in the 70's. Since then, I've had numerous 2-stroke trimmers, leaf blowers, chainsaws, etc. I'm just a homeowner, and I've never operated a 2-stroke engine commercially, but I've never had one die. For power equipment that I'm carrying (chainsaw, trimmer, etc), it's 2-stroke all the way for me. They're lighter than their 4-stroke counterparts for the same power, so I can carry it longer, and get more work done.

Now my riding mower is different. It has a 27hp EFI engine, and two 3.5gal fuel tanks. It takes 2 hrs to mow my yard, and I can mow it at least 3 times on that much fuel. If it were a 2-stroke, it would probably use all 7 gallons each mow.

Are 2-strokes fragile, temperamental, finicky? I don't think so. Maybe slightly more than a 4-stroke, but if maintained, both will be reliable. If ethanol fuel is left in them over the Winter, it won't matter whether it's a 2 or 4-stroke. Neither will start, and both will need a carb cleaning or rebuild. In 2011, I bought a mower with a B&S flathead engine, and an Echo 225 PAS system. I liked the Echo PAS system because it meant only one engine to maintain for all my handheld OPE. It also meant that there wasn't any piece of equipment that didn't get started for weeks. The Echo has been run, I'd say, about 75% as much as the B&S, and they both still run like new today, 14 yrs later.

My RD350 consistently gets 38 MPG. I spent a LOT of time tuning.

Smithsonite said:

My RD350 consistently gets 38 MPG. I spent a LOT of time tuning.

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OK, but that RD weighs (according to Wikipedia) 342lbs. A truck weighs over 10X that. Although I have to say, that must be a VERY well tuned RD. My 4-stroke bikes never got mileage that good.

It also has MANY modifications. Carb mods, reeds, porting, pipes, higher compression, different pistons, crank balanced, etc.. I got the squish set within .001" of where I wanted it, and run the timing advanced farther than anyone else with the same bike dares. Runs absolutely perfect. I figure around 70HP at the crank, maybe more. She rips!