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2 cycle engine running problems

Discussion in 'Non-Mopar Tech Support' started by AllanC, Jun 20, 2017.

  1. Muther

    Muther Well-Known Member

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    1) Your tank almost certainly has a fuel filter. Pop the tank off and see. Replace it.

    2) Go to O Reilly's and get the correct length of fuel line of the proper inside diameter. Make sure it is actual fuel line, and not something else. Replace the fuel line.

    3) Replace your air filter. Do this annually on all your small engines. Clean your air filter regularly. Clean it more often if you have dusty and dirty conditions. DO NOT WASH IT. Just shake it out as best you can. If you absolutely MUST wash it, do so, then smack your forehead with a claw hammer. Seriously, DON'T wash it. The water present in the filter when you reinstall it WILL harm the engine. You could by two, install the brand new one. Wash the old one. Let it dry for a week until you need to mow again. Then swap them, repeat.

    4) DON'T CLEAN YOUR PLUGS. Replace them. They are a couple bucks. Replace annually.

    5) Use Stabil or other gas preservative all the time. Use the highest octane gas you can get. Not for the octane, but because it usually comes from better storage tanks at the fuel depot before it even gets to the station. Buy gas from the most reputable station you can, Phillips, Sunoco, Shell, Union, Etc. All of these folks sell gas to other gas station brands. However, they only sell the BEST gas to their own brand. Joe's Cigarette's and Gas will only be able to get the crappy grade, stored in the worst tanks, and Joe's tanks are likely crappy, too.

    6) After all that replace the carb, or just rebuild it. Clean it with compressed air and carb cleaner. If you don't have a compressor, just buy cans of compressed air for computer cleaning.

    7) if after all that it still doesn't work, throw it out and buy a Stihl. Buy your small engines from a small dealer. Avoid any brand that is sold at box stores (which now includes Honda and JD). If you buy from Walmart, I am sorry, but you deserve what you get.

    Ariens, Gravely, Grasshoper, Stihl, those are good brands. Expensive in the short, cheaper in the long.

    Troybilt is MTD. They are a shadow of what they once were.

    As always. Wear eye protection. Be safe.

    Also, place a call to MTD/Troybilt. Complain. Say that you love the brand. Give them a tear jerker of a story, who knows, maybe they'll throw you a bone. It has worked for me in the past.
     
    #21 Muther, Jun 21, 2017
    Last edited: Jun 21, 2017
  2. Bob Lincoln

    Bob Lincoln "CHECK FAULT CODES"
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    My understanding is that with gasoline appliances, you are supposed to add Stabil and then run the fuel supply dry, to store it for winter.
     
  3. AC TC

    AC TC Well-Known Member

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    Sparkplugs on a twostroke can be tricky, Always replace if its any doubt...
    - i run all of my small Equipment on alkylate" syntetic" gasoline. (pre blended for two strokes of course.)
    This have almost completely made the "start em up in the beginning of the season" problems disappear.
    Besides it better for both the enviroment and operator both from handling Point and enviromental Point.
     
  4. Doug D

    Doug D Virginia Gentleman

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    From Google:

    How do you use fuel stabilizer?

    1-ounce (30-milliliter) treats up to 2½ gallons (9.5-liters) of fuel. Use STA-BIL only with fresh fuel, and keep gas can or tank 95% full to avoid condensation build up in tank during storage. Run Engine for 5 minutes after adding product to treat entire fuel system.

    How long will fuel stabilizer last?

    STA-BIL® Fuel Stabilizer will keep fuel fresh for up to 24 months, guaranteed. Depending on the quality, type and source of the gasoline, as well as storage conditions, doubling the dosage rate of STA-BIL® brand could prolong this storage time to up to 2 years.

    I found the following website and did not see anything about adding Sta-bil and then running the engine until the tank is empty.

    How to Use STA-BIL® Fuel Stabilizers, Treatments - FAQ (at https://www.goldeagle.com/brands/sta-bil-faqs )
     
  5. Tomguy

    Level 2 Supporter

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    FWIW modern 2-smokes are set up to run pretty lean and usually have non-adjustable mixtures (locked mixture screws). Coupled with a 50:1 ratio, the cylinder walls and piston will often score within 3-4 seasons - faster in heavy use. IMO on a $60-80 trimmer, it's not worth putting $20-40 in parts into it to try to troubleshoot it or tune it up. I love my Stihl 2-stroke trimmer - it's about 20 years old - but it's heavy, it vibrates, it's loud, and it's smelly. My wife bought me a LiON 24v trimmer for father's day, for $70. I already love it.
     
  6. Bob Lincoln

    Bob Lincoln "CHECK FAULT CODES"
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    upload_2017-6-22_15-48-12.png $16, no emissions, always work.
     
    chuzz likes this.
  7. Muther

    Muther Well-Known Member

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    Also, always remember, with two strikes the amount of oil in the gas-oil premix plays around with jetting. Add to much oil and it displaces gasoline. This create a lean mix in the engine. Too little oil and you get a mixture that is too rich, because there is less oil to displace gasoline. The gasoline "fills" in the gap.

    Do pay attention to gas mixture.
     
  8. Tomguy

    Level 2 Supporter

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    It takes me a good 30-40 minutes to use the power weedwhacker. I'd hate to see how long that would take me!
     
  9. dana44

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    How long did you run your weed wacker the last time you used it? The reason I ask is because I went through two of them in four years because I would run four tanks of gas through them and they basically melt. Last one I had lasted 9 years by running no more than two tanks of gas and letting it cool down at least half an hour before continuing. Just replaced my 9 year old Ryobi because the fuel tank eventually started leaking and couldn't get a replacement tank so purchased another one. Has to be something serious with the compression if starter fluid won't start it, given it is so flamable, if you have spark, it basically bypasses the carb and fuel lines and should run a couple seconds no matter what.
     
  10. AllanC

    AllanC Well-Known Member

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    It ran about 20 minutes and then hiccuped and stalled. I have disassembled the carburetor and cleaned thoroughly with spray carburetor cleaner. I reassembled but spinning the crankshaft with an electric drill only gets an occasional fire and run. But it will not run on its own. But reusing existing gaskets could have introduced vacuum leaks and on a small displacement engine, that could lead to a no-start condition.

    I have ordered a replacement carburetor through Amazon. I am waiting for delivery from China so it may be next week before I get it. Hopefully this will solve the problem and the trimmer will run;.
     
  11. 68RT

    68RT Well-Known Member

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    Over an acre of grass, 20+ trees (evergreen forest next to me w/ 7 on my property) plus cherry, apple and more trees, 400 feet of gravel driveway, 200 feet of shrubs on one side of property alone plus others. Give me a lot of power! Still three hours a week.
     
  12. Bob Lincoln

    Bob Lincoln "CHECK FAULT CODES"
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    You don't mow trees, driveways and shrubs. Just grass. I can mow grass with a reel mower as fast as my neighbors do with their riding mowers. And it gives me exercise that keeps me alive.
     
  13. gezco

    gezco Well-Known Member

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    You know you can buy premixed 50:1 gas at Home Depot and other garden centers? It's pure gas and oil. It's around $5 a quart but my chain saw really runs better on it. I think it's 90 or 92 octane.
     
  14. dana44

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    Yeah, but even with, and I have done this after being deployed a time or two, used gas as old as two years, properly mixed originally, just shaken up to remix it, once it starts and runs, to which the starter fluid should have fixed that issue, even if the air cleaner was a little dirty, once she is warmed up should be able to run the poor quality fuel. One other thing I have found out (yeah, clean the air filters, a dusty environment doesn't do well with them sometimes), but, the plunger/primer bulb. I have had a couple of them deteriorate and leak fuel or suck air, usually the latter, and if you can hold your finger over the bulb and push it once she starts running and dies after you release it (after a few seconds), change the plunger/primer bulb.
     
  15. AllanC

    AllanC Well-Known Member

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    I took the gasoline trimmer to one repair shop. I was told that the piston and cylinder barrel are ruined. Repairman could tell by the drag on the pull cord. He must be fortunate to have a "calibrated arm muscle that can detect a heavy pull!!!!!"

    I got a compression tester. If I use an electric drill to spin the crankshaft for 10 seconds I get a maximum compression pressure of 105 psi. If I use the pull starter cord and pull vigorously 6 times I get 60 psi compression. From YouTube videos I am gathering that is low compression???

    I wonder if a blocked exhaust port with carbon could affect breathing and lead to a low compression reading? I will check the exhaust port.
     
  16. dana44

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    105psi is kind of low, 60psi is dead. Pull the spark plug out and look inside the cylinder, see if you can detect any scratches. You can also pull the head or barrel off (four screws or bolts, and look at the condition of the cylinder wall and piston/rings. If they are good and no galling or scraping of fusing (piston and rings), it's not like 4 stroke where everything has to be replaced to keep working. At this point you have nothing to lose, it doesn't start anyway.
     
  17. Muther

    Muther Well-Known Member

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    2 strokes are waaaaay different regarding compression. No idea what they run, or if it's even a relevant test, or even the proper method to do the test.

    Four strokes live an die by compression; it is very likely mportnat for them. Two strokes, not so much.
     
  18. NYBo

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    Low enough compression and a 2-stroke won't start. With outboards, that's usually below 90 or so. Not sure for a weed-whacker, but probably similar.
     
  19. AllanC

    AllanC Well-Known Member

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    I removed the muffler and looked at the exhaust port. It is clear and not clogged with carbon. I moved the piston up and down. There were some marks on the rings but I am not experienced to say they are sufficient to lower compression. Maybe rings should be shiny and show no scratches?

    I did some internet searches and it seems you need at least 90 - 100 psi to get the engine to start. No way I can get 100 psi with pull cord. So I think I am beating a "dead horse" at this point in time in trying to get this engine to run. Either replace the engine alone, replace the entire trimmer with another Troy Bilt unit or buy another brand gasoline trimmer are the options.

    I still would like to know what caused this compression failure? If you let the gasoline - oil mixture sit unused in a container for 1 - 2 months gasoline has a higher vapor pressure and would have a much greater tendency to turn to vapor and escape the container. If that situation occurred, you would tend to have a higher concentration of oil in the remaining gasoline. More oil to gasoline in proportion will not damage a piston and rings.

    I appreciate all the helpful comments.
     
  20. dana44

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    Hard to say what made it go bad. At this point, you could pull the cylinder off, see if the rings are free of the piston, can't hurt at this point. Never really had a problem with old gas/oil, just shake the can before pouring it in, have mine sit up to 7-8 months at a time and start right up with old gas sitting in it all that time, had four year old gas I siphoned and have used it that way without an issue, too. I've been using Ryobi for about the past 20 years, gone through three, the second one is still good but the tank itself leaks so not safe to run, they don't make the same model anymore, so got another one, run them about two hours at a time (two tanks of gas) and let it cool half an hour and keep it up. Guess if you have to get a new one, play with the current one to see if you can get it working, low compression kills most of them from overheating and melting piston rings to the piston. What can I say.
     

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