Small Engine Repair Problem?

I have a small 2 stroke engine from an old snow blower I want to use for a project. It gets a spark, appears to have good compression, but still won't start. we tried it with the choke open and closed, with the throttle all the way open and closed as well. I took off the carb, and it appears to be alright. When I took it out some gas came out, so i am fairly sure the engine is getting fuel. Any ideas as to what could be wrong?


The fuel isnt old at all, maybe a month or two, which shouldnt be too old.

6 Answers

  • unk
    Lv 4
    9 years ago
    Favorite Answer

    Two cycle engines can be very tempermental. They're great when they run but a bugger if they don't. Did the engine run when last put away? If not, when was the last time it was run and what - if anything - odd happened. Did the neighborhood "handyman" work on it? That'll be a good clue (e.g., it just stopped or the previous owner hit a rock/tree/moose with it). You'll need to know for next guy's diagnosis.

    Until then, there are a couple tests you can do. There are two common reasons for a 2-cycle to not run - fuel and fire.

    Dribble a LITTLE gas into the intake and crank it. (DO NOT USE STARTING FLUID!) If it fires, you have an issue with one or more of the following: fuel filter, carb, fuel line, fuel pump or impulse line (hose from crankcase to the pump or carb). If there was ANY fuel in the carburetor longer than 6 months, then you'll likely need to rebuild the carburetor. Lines are an easy fix, as is the filter. Fuel pump, if not integral with the carb, will need to be cleaned and (possibly) rebuilt. Kits for these are readily available at a store that sells the brand of implement that the engine came from. Make sure you mix the fuel (gas+oil) correctly.

    If no fire, you have an electrical issue; one or more of the following: Spark plug, plug wire, coil, points/ignition module. Check spark by laying a plug on the engine shroud and cranking the engine. The spark needs to be bright blue and strong - across the entire electrode - not weak (orange thread).

    Weak spark = spark plug, wire, points/ignition module. The first two are easy - replace them. Second two are a pain b/c they require pulling flywheel (most the time, anyway). Last one can be downright expensive.

    If you have strong spark AND fuel, then it's possibly timing. Remove flywheel nut and look at the keyway to make sure it's not sheared. If ok, its not timing.

    There IS the possibility that the crankshaft seal(s) is(are) bad. One of the more common places is where the crankshaft exits the crankcase (PTO end). Try to move this around. If any play, this is your problem. Leaking seals will allow the engine to suck air from any one of a few places. The only air coming into the engine must be from the carb intake.

    If none of these, then it falls into the 2% of issues and stumps me.

    Good luck.

    Source(s): Several years' experience w/2-cycle engines.
  • Moe
    Lv 6
    9 years ago

    unscrew the spark plug is it wet with fuel ? try to start it with the spark plug out and touching the side of the engine block .is it sparking ? put a white mark on the flywheel at top dead center ..see if the spark plug is sparking when the white mark is at top dead center or just before..all you need to get a engine to run is fuel ,,air and timed right ..change the fuel to make sure it is good not watered down ..make sure you are getting air and check the timing..

  • renpen
    Lv 7
    9 years ago

    Remove the sparkplug, put a teaspoon of fuel into the hole, replace the plug and try to start it. If it starts and quits, rebuild the carburetor. If it doesn't try to start the sparkplug may be bad. You could have an air leak around the carburetor, check all fasteners. The compression may be low. You said that it was ok but you didn't say what it was or how you checked it.

  • 9 years ago

    A month or 2 is OLD, [gas] for gas mix, all of the gas evaporates and leaves a oily mess

    the only thing that will keep a 2 stroke from running is spark & gas,& oil mix

    50 to one on the mix,

    Source(s): old timer/small engine mech
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  • 5 years ago

    Regardless gas goes bad after 30 days, and if the gas has ethanol in it, there is your problem, clean the carb, and maybe apply kit and put fresh straight gas in the unit and see where that gets you

  • 9 years ago

    Is that NEW fuel or OLD STINKY POOP that's been in there for years?

    Old gasoline is like kissing your great aunt, the passion is lost somewhere.

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