Older sears mower won't start / stay running

williaea(pa)May 10, 2009

I picked up an older mower from a friend and am having trouble getting it to stay running. If I pull the plug and hit it with some straight gas it will often start and run for 2-3 seconds - so I'm assuming I have adequate spark. I have yet to get it to run using the primer. I'm used to the Lawnboy 2 cycle primer feel and I have no clue if this engine should have that same feel (creating a vacuum feel when you prime the lawnboy). It doesn't have much of any feel at all when I push the primer. Anyways - beyond that I have pulled the head. The piston and valves are moving normally. I have pulled apart the carb and cleaned it. I have pulled the top end off and sandpapered the ignition coil and flywheel. The engine says it's a 143.986700 (model) from 1998. I'm guessing it's a tecumseh engine as I've worked with Briggs engines a little bit and this doesn't look like one (But I'm not certain).


What should the ignition coil gap be for this engine?

Any clue of what I should be checking to try to get this guy running? Thanks


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Magneto gap 0.01", or a business card.
Does it have a brass bolt in the bottom of the fuel bowl with orifices in it? Take it out and clean them, including possibly a tiny one near the top of the bolt - use wire tie wire to rod it out, then blast with carb cleaner.

    Bookmark   May 10, 2009 at 11:16PM
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Thanks for the advice. Unfortunately after a week of being deathly sick (OK not quite dealthly - but sick enough I didn't feel like screwing with the mower) I pulled it apart last night and unfortunately it has no brass bolt. Carb bottom is black plastic, main orifice appears to be white / yellow plastic. Couple springs. Did carb clean stuff out and wire tie wired some openings, but no luck. Main jet orifice seems to have a black rubber gasket on it. Doesn't look great - but should be good enough to seal. Any other ideas? .010 was my original guess when I had the magneto off a couple weeks ago so that should be OK. Thanks.


    Bookmark   May 20, 2009 at 7:56AM
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Does that carb use a diaphragm? Replace it?

    Bookmark   May 20, 2009 at 11:25AM
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