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The Something Awful Forums > Discussion > Automotive Insanity > Small Engine Repair Thread
 
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opengl
Sep 16, 2010

 Any pro tips on setting the low/high mixture screws on a 2 cycle? Trash picked a 25cc Craftsman blower which looks like it got curbed for gummed up/disintegrating fuel lines (thanks ethanol). Was going to just order new lines but the air filter was soaked too and I also needed a fuel filter/sinker, and it was cheaper to buy a whole carb kit with all of the above plus a new carb and plug and some other bits and pieces. Anyway, got it running but its badly in need of adjustment. Stumbles a bunch, only really stays running on half choke and wants to die when I give it throttle unless I do it really gradually. Just waiting on the screwdriver so I can adjust it (sorry not sorry EPA).

Also last week brought a really nice trashpicked Craftsman/B&S back to life by installing a $4 air vane spring, which the previous owners had tried to bodge together with a MASSIVE wad of electrical tape and sandwich twist ties. I don't get it but it's a lot nicer than my mower and self propelled too.

Yes I've been watching a lot of mustie1.

opengl fucked around with this message at 19:38 on May 21, 2020

* # ¿ May 21, 2020 19:36
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# ¿ May 9, 2024 23:16
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opengl
Sep 16, 2010

BalloonFish posted:

It sounds like it's running too lean (hence why it needs the choke and suddenly opening the throttle plate kills it). When setting carbs I've always favoured just running both screws all the way in (gently so as not to squash the tips) then backing them both out one full turn, so you'll be in the zone where it will run but almost certainly too rich.

Let it run for a minute to get up to temperature then ease out the low-speed screw (usually less than a quarter of a turn) until you get the smoothest running or the fastest idle - some engines, especially two-strokes, seem to rise slightly in idle as they approach the ideal slow mixture then fall off as it goes too lean.

Do the same with the high-speed screw with the engine running on full throttle - slowly unscrew it until you get the smoothest/fastest running. Ideally you should then run it in a tiny bit so it's just slightly on the rich side.

You should then get an engine that idles smoothly, runs well at full speed and doesn't stumble when going between the two. If it does then open out the low-speed jet a little or raise the idle speed a bit.

Thanks! Screwdriver set arrives today so I'll give it a whirl.

Nidhg00670000 posted:

I've always run all my smaller stuff on alkylate gas, it seems a lot more stable than regular pump gas and apparently it's much better for emissions as well.

I picked up TruFuel to run in it since you can't get ethanol free gas at the pumps here. A little expensive but premixed and no worried about loving corn sauce gumming up the works.

* # ¿ May 23, 2020 16:52
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opengl
Sep 16, 2010

 Running great now, :cheers:

* # ¿ May 24, 2020 21:10
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The Something Awful Forums > Discussion > Automotive Insanity > Small Engine Repair Thread