Model #917379810 CRAFTSMAN Walk Behind Lawnmower, Gas

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Question and Answers


My rotary lawn mower was left idle for some time and now will not start?


One of two things is happening; either there is too much fuel and the engine can not use it all, or there is the correct amount of fuel but the engine is unable to draw it in for some reason. The engine can only use so much fuel and any excess fuel cannot go back into the fuel supply so it goes out the other opening for the carburetor, which is normally used for incoming air and is where the air filter is.

The most common cause for that is old or low grade fuel that will not burn completely and begins to accumulate and add to the fuel you are adding when you prime or choke the engine. If you already tried new fuel, and even drained the old fuel from the carburetor, there may be something plugged or stuck inside the carburetor that is causing too much fuel to go through. That can happen after the unit sits and fuel evaporates leaving behind a sticky residue. In that case the carburetor may need to be cleaned or replaced to get all the residue out of the tiny orifices (see images below). We recommend a professional do any carburetor work not covered in your owner’s manual to assure it is repaired to full performance without alter any emissions standard.

Even if the fuel is being delivered properly, there are a few reasons why the engine might not be able to draw the fuel in. Something might be blocking the intake area the fuel and air needs to go through. Or, a valve might be out of adjustment so that it does not open at the right time for engine vacuum to draw the fuel through. Or, the engine might not be creating enough vacuum to begin with due to wear or a part failure. Sometimes the piston rings will stick or dry as the unit sits and then they do not seal enough to create the needed vacuum and compression. In that case, putting a small amount of oil into the spark plug hole might get the dried out or stuck piston rings to seal enough to get the engine running again.

- To view the Owner's Manual online -

Go to the Home page of Manage My Home and hold your mouse over the square labeled HOME in the upper left of the page. A drop-down menu will appear, choose the option Products and manuals and then enter the model information and follow the steps.

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Sears Technician
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