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Carb adjusting screws

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  • Carb adjusting screws

    My 2 cycle lawn edger (Weedeater) refused to run properly today. Could get it to run on half choke, but at full throttle it kept dying. The carb screws do not have screwdriver slots but a sort of splined head to prevent "unauthorized" adjustment. I went to the local lawn equipment place, reputable and has served me well, and was told that the adjusting tool was available but cannot be sold to a consumer. I found the tool on the internet, no questions asked, for less than $10 shipped. SO I chucked up a piece of ABS turn it down to 1/4 in ,drilled a .164" hole, warmed up the end and pressed it over the screw head. A 1/4 turn richer on the high end and it is running better than it ever has. i KNOW that, had I brought it to the "authorized" dealer , they would have done the same thing.Probably would have cost me $50 or more. just MAKES MY DAY when i can beat the "system". Bob Fisher

  • #2
    I absolutely hate the NEW carbs on the small engines now. Most of them are not adjustable and those that are need special tools. The engines out of the box are seldom correctly adjusted.
    It's only ink and paper


    • #3
      Did you clean/replace the fuel filter and air filter? I have two cycle equipment around here that sits for years without use then gets used for months straight*. I've never once had to adjust the carb on any of them.

      *That's how it goes here in South Texas. Rains some years, but mostly not.


      • #4
        Protip: If it used to run and no longer does, Its one of two things:

        4 stroking/choke kills it instantly = Too rich = Cloged air filter, Maybe sunk (leaky) float or other carb problem.
        2 stroking but 'missing' ignitions, sometimes going a few revolutions beween ignitions, Sounds like outta fuel, partial choke fixes it = too lean = Cloged fuel filter and/or jets. Or maybe some other carb problem.

        Kindly, Fix the fuel filter/clean the jets, Don't adjust the carb

        The only time a carb adjustment might be needed if it 'used to be working' is when going from an extreamly hot running climet to a cold one.
        Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.


        • #5
          Have four other 2 strokers,blower, hedge trimmer,snow blower ,weed trimmer, and chain saw. Make that five. Most are older than this one,bought in 03, no other problems.I stabilize the fuel each season and clean the air cleaners each season as well. This one, come to think of it, ran lean right from the get go. I love 2 cycle engines, they pack a lot of power for their size and don't need 100 ' of extension cords dragging along.


          • #6
            In my experience these small motor carbs are very prone to getting a small piece of dirt stuck in some passage that makes them run like poop.

            I've had good luck taking them apart, blasting them with carb cleaner and compressed air and then reassembling.

            Paul T.


            • #7
              Had the same problem last year with my blower. It would run at full throttle for awhile and then die. Run it at 1/2 - 3/4 choke and it was OK. Adjusting the mixture screws didn't help any.

              At the end of the fall season I was cleaning it up for storage and found a small crack in the primer bulb allowing it to suck air. Replaced the bulb and it runs like a top again.


              • #8
                I got a "Weed Eater" right now with that same problem.Will only run on half choke, and will not rev up fully.

                On inspection i found while pushing on the primer bulb, i noticed a very fine stream of fuel comming out of the side of the plastic fuel line.
                A pin hole in the line.

                Going to get a new line and relace it.


                • #9
                  Thanks for all the tips, if the problem come back, I will look for other causes. For right now,I am happy. Machine screams like a banshee, like a 2 cycle should. Aside from that, anyone ever driven an old Saab with a two stroke engine? Seven moving parts ,so they claimed. How high did they rev? Regards, Bob.


                  • #10
                    Seven moving parts? holy thats a lot

                    My bikes motor has... Lets see.
                    Piston. Crank arm. Crankshaft. Top and bottom bearings (Assuming they count) And well, I guess the side bearings. Ok 7. If you count bearings that is... (Well, technicaly more if you count each ball bearing and the race but.. whatever), 3 if you don't count the bearings
                    (or the clutch, Or the transmission.. etc)

                    All the valving is done by the piston itself. Ignition is electrical off just a magnet on the crankshaft and a coil.
                    Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.


                    • #11
                      Those danged weed eaters are an amazing little machine. I bought mine 11 years ago for $89.00 tax in. A number of times i caught the string in raspberry bushes, fence wire etc enough to stop it dead!!
                      A single pull , and away it would go again.
                      Thought many times the driveshaft would break getting it caught like that but so far not!!
                      Over that time i,ve found three more at the landfill, two to keep for parts,, and one i just gassed it up, it fired after three pulls and ran great.
                      Now need a diaphram for one,, and when i checked at the dealer for a diaphram, there are three different ones!! So gotta take the old one in to match it up.
                      Hard to believe in this day and age an $89.00 machine would last this long.


                      • #12
                        This Weedeater is an edger. They stopped producing them due to a very high failure rate of a sintered drive gear.I have been careful with mine, armed with that knowledge, and if the gear finally bites the big one, I shall undertake to make a proper steel replacement. It's not as though noise is an issue. Bob.


                        • #13
                          The Saab autos that I mentioned earlier were 3 cylinder 2 stroke engines. 3 pistons, 3 rods, and a crank. Never had an opportunity to drive one,but they sounded like popcorn poppers at idle. Bob


                          • #14
                            My two cents is that those tiny Walbro carburetors are prone to plugging up, and are a pain in the rear.


                            • #15
                              The "carb adjusting tool" you described is actually a Torix bit commonly used in gunsmithing. I had to buy one when I was still working, to replace the distributor cap & rotor on a 5.7L LT-1 Chevy V-8. I think they might have a set of the smaller Torix bits with plastic handles at "Horror Fright".

                              Most small engines like the ones used on something like a "weed-eater" are usually designed to be used until they don't run any more, then you throw them away and buy a new one. The only reason a lawn tool repair shop would refuse to sell you the tool is if you lived somewhere near a bunch of "tree-huggers" or if they had the EPA breathing down their necks.
                              The use of two-stroke engines for garden and lawn tools was supposed to be banned, due to the large amount of pollutants emitted by them. The EPA Nazis want everybody to use clean running four-stroke engines or cordless electric power. I suspect they're going to move into two-stroke model aircraft engines next, even though the majority of them run on methanol.
                              No good deed goes unpunished.