My Parents gave me a Craftsman Yard Vac (Model No. 247.770550) that they hadn't used in a few years. The tank had been empty, but mice had made a nest around the engine. I chased the mice away and fueled up and it worked fine. I cleaned it up for winter, removed a few dead mice and their nest, put some sta-bil in the tank and ran the engine for 10 min. This fall it would not start, I replaced the spark plug, air filter, oil and gasoline (this time with TruFuel). I also took off the housing and cleaned out the rest of the mouse nest. Still no luck. I then decided to clean out the carburetor, it was pretty dirty. I replaced the pin & seat, bowl gasket, and the sealing washer and cleaned everything with carb spray, a paper clip, and a toothbrush.

The Vac now starts but will only run with the choke fully on, and will die after ~2 minutes.

I'll add that after reassembling i had gas leaking all around the carb, i tightened the main jet bolt and it stopped. Also, after using the vac for a little while i had another gas leak out the carb where the air filter hole is (this was after it sat for 5 min), but this stopped quickly.

  • Choking it helps the engine suck harder on the fuel supply. To need to choke, it sounds like there is still gummed up fuel somewhere. Have you adjusted the mixture screw (lean/rich)?
    – donjuedo
    Nov 25, 2015 at 1:38

3 Answers 3


I just "refurbished" a pressure washer that had set for a while. I cleaned the carb and got it to where it would start, but it would only run with the choke on.

Through some online research and trial and error, I determined that when choked, the fuel takes a different route through the carb. I had to remove the main jet and associated parts, soak them in carb cleaner for a while and clean all holes with a wire much finer than a paper clip. I could only find carb cleaner in a spray can, and I didn't want to purchase a whole gallon of chem-dip, so I just used the spray can to fill the bottom of a glass jar which worked fine.

Once that was done it ran better, but only for a few minutes. On a hunch, I tried running it for a while with the gas cap off, and it worked. Turned out the vent hole in the cap was plugged by a spider or who knows what. After widening the hole a bit, it ran for the rest of the day.

Forgot to mention: Don't get carb cleaner on any of the rubber seals. It makes them expand, and when they dry they will shrink back to shape, but it's bad for the rubber.

Not the most exact answer, but hope it helps!

  • Nice extra about taking a different path through the carburetor. +1
    – cdunn
    Mar 17, 2016 at 21:25

Purchase some "Chem-Dip", remove the carburetor and break it down to single parts, put aside all plastic parts and soak all metal parts as per directions. Check your bowl float port , it may have debris lodged in it that is hard to see. After soaking in cleaner use compressed air, not metal probes, to remove residual cleaner and crystalized fuel. The carb may or may not have fuel adjustments (probably not if you live in California and it was purchased after 1990). If they do check the ends of the needles, they should not be blunted or have burrs, but be smooth and tapered. The fuel leaks could indicate the float is stuck(likely) or at the wrong level(possibly) or the gasket needs replacing and bolts need tightening. Don't use gasket sealer at the carburetor throat as it poses a danger of clogging intake. And check that your gas cap (if vented) is unobstructed. Keep us posted.


You can purchase a aftermarket carburetor for it on Amazon for about $15. I had a similar problem with my craftsman mower and did exactly this.

You need to find the manual for your machine online to confirm the part number. Mine used a Briggs and Stratton part #499059.

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