Craftsman mower won't start/prime

zanepsJune 12, 2010

I have a Craftsman mower, model # 917.385127, with a Briggs and Stratton engine, 5.50 ft-lbs torque, 158 cc. It's less than a year old, and I think I've only used it 5 times.

I was mowing yesterday and it died. It had plenty of oil and gas. I started it again and a bunch of white smoke shot out the side. It started but died within a few seconds. I couldn't get it to start again after that.

When I go to push the prime button, it feels and sounds like nothing is happening.

I checked the air filter, it was pretty clean, but I cleaned it anyway. I cleaned it with a little gas (from reading some on this forum). Tried to start it again, it started, but died immediately.

Any help would be appreciated. I don't know much about lawn mower engines, so please dumb down your responses a little.


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Does it have a fuel shut-off valve that might be closed?

    Bookmark   June 12, 2010 at 5:43PM
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Does it have a fuel shut-off valve that might be closed?

    Bookmark   June 12, 2010 at 10:30PM
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If this is a carb on fuel tank model, I would replace the carb, give the tank a quick clean whilst you are at it and you will be back in business. Parts are cheap. Sometimes the little plug falls out that plugs the primer passage.

    Bookmark   June 12, 2010 at 10:38PM
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It doesn't have a fuel shut off valve that I know of.

Can you tell me how to check if the plug has fallen out of the primer passage?

    Bookmark   June 13, 2010 at 4:11PM
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Try replacing the diaphragm.

3.75 Briggs carb rebuild

This is an easy DIY job to replace the diaphragm of the carburetor. A damaged diaphragm will cause engine surging, hard starting, and erratic high speed operation. You may also notice that the primer bulb isnt working properly.

This is an overview of the carburetor and these types of carb-over-tank are typical of small Briggs engines. Note the two governor springs. The carb/tank assembly is held in place by a ½" bolt to the left of the carb and a 3/8" bolt on the engine head to the right. Remove both bolts and pull the tank straight out with a rocking motion. If possible, the carb/tank assembly should be blown off with compressed air and all loose dirt removed. Use the proper safety equipment, especially safety glasses, before using any compressed air in any of the steps below.

In the highlighted area you will see the governor linkage still in the throttle plate of the carburetor. You will have to gently separate the carb/tank assembly from the linkage. It is a Z type linkage. It is not necessary to remove the springs or the other end of the linkage, from the governor.

Note that on the rear of the carburetor is found a white plastic ring and O ring. Sometimes these remain on the tube of the engine housing. If so, place them back into the carburetor body, as shown, before reinstalling the carb/tank to the engine.

Note the raised area of the diaphragm. This is caused by age, but more often, by ethanol fuels, which damage the diaphragms. A damaged diaphragm will cause engine surging, hard starting, and erratic high speed operation. You may also notice that the primer bulb isnÂt working properly.

Shown here are the dip tube, which brings up gas from the tank, in the bottom left corner. Just behind that and partially obscured, is the orifice that compressed air can be used to clear the dip tube of debris. It also leads to the primer bulb, so any air must be low pressure and the primer bulb must be held in the depressed position to prevent it from blowing out. In the center top, youÂll notice the jet, surrounded by a wire mesh filter. In the bottom right is a spring. Be careful to not lose the spring or forget to install it during reassembly.

Remove the old gasket and diaphragm combo from the carb body. Install a new gasket/diaphragm on the smooth surface of the tank. I always blow out the tank with compressed air to remove dirt and any water. Be aware that there may also be old gas in the tank. I always empty the tank and let it sit in the sun until all the gasoline evaporates before applying compressed air. Align the carb and lower it down on top of the gasket, trying to keep the five screw holes in the gaskets aligned. Insert the screws and partially tighten them and install all five screws. Tighten each screw until it gently bottoms out. Then turn each screw another quarter turn. It is not necessary to use more than a few inch pounds of torque on these screws. Reinstall in reverse order. When installing, be sure to engage the breather tube with the rubber piece on the carburetor.

    Bookmark   June 13, 2010 at 5:41PM
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Bayme has great pics! It would be the BB you see in the 4th picture below the fuel pipe. In my experience, if they don't prime- they get replaced.

    Bookmark   June 13, 2010 at 7:49PM
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We had the same, exact problem. Same mower, only used it a few times. Long story short, we isolated the issue to the Operator Presence Control Bar's functionality. Pull the control bar back, and observe where the wire attaches at the rear of the engine. Remove the plastic engine cover to expose the control bar mechanism, and you will see there is a flange that pulls back from an upper point connection. Our's was coated with grime from mowing. We cleaned it off. The mower residue had collected on this connection, preventing a proper read. Super simple fix and no carb clean required. The mower is working like the day we bought it. Hope this helps.

    Bookmark   July 24, 2010 at 6:55PM
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Whoa!! Time out!! This mower has a 2-year warranty. If it's less than 1 year old, take it back to Sears for repair or replacement. Check the owner's manual.

    Bookmark   July 25, 2010 at 1:00AM
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Junebug: I think you are on the right path . I would return for service if within a yr old .

Kris: The kill function on the Bail would not permit starting . This is not the problem on this mower.

Baymee: I don't think a Carb Teardown is warranted Yet !

Zan: I believe your main fuel supply circuit (main jet) is gummed up) also the primary priming circuit and lines are also gummed up most probably do to residual fuel (Ethanol) left within the carburetor and associated fuel lines . Buy some concentrated fuel cleaner and treat the gas and spray some within the primer line and main carb jet . Let the gas cleaner work for approx 30 minutes and try restarting it may take a few tries to run the treatment through . The Primer should begin to function properly also within a few attempts. Otherwise compressed air or computer duster spray may be required to assist with forcing the cleaner through . Once started let the engine idle for a few minutes prior to attempting to increase the throttle or commencing cutting. Hopefully the diaphram has not been damaged , but may require replacement per Bays illustration if all else fails .

    Bookmark   July 25, 2010 at 9:15AM
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Don't hesitate to call your local Sears repair center. They can check if it is under warranty or lead you in the right direction. There is also the community with Craftsman experts. If those don't work you can email me at

    Bookmark   July 26, 2010 at 3:20PM
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I have a Thank You to to Baymee and Ewalk for their postings from last year. I bought a Yardman mower with the Briggs & Stratton 158 cc motor last June. I used it once and a week later it wouldn't start. It would fire when primed and then quit. I needed to return it but didn't. Now it's April 2, 2011 and I want to use it. It did the same thing as last year, but this year I found this web site. Ewalk's July 25, 2010 post made me think it was the main jet. I didn't know where the main jet was located. Baymee's earlier June post has great pictures and it showed me that the main jet was under the mesh filter. I took the carb off and used carb cleaner to spray into the main jet. I also sprayed the cleaner into the gold air bleed on the other side of the carb. I put the carb back together and it started and kept running on the first pull. I just got done mowing for an hour and half. Thank you Ewalk and Baymee.

    Bookmark   April 2, 2011 at 6:31PM
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Quartz10: Very glad to be of some assistance . We are very fortunate on the forum to have the access to picture tutorial displays available from Bay , Mownie and Ipod , they make troubleshooting through illustrations much more clear for members new to small engine repair . Thank you for taking time to update us on your repair all the best !

    Bookmark   April 3, 2011 at 10:07AM
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