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Small Engines (Lawn Mowers, etc.)/lawn tractor starving for gas


JohnnySuperDad wrote at 2013-05-20 23:40:52
     I had the same problem with my Sears Craftsman LT2000, Briggs & Stratton 20HP mower. Runs for 15-30 minutes then starves for gas and dies. After 5 minutes starts right up again runs for 10 minutes more then dies again.

    Sidenote :I found out part number 33940 (original fuel filter) has been discontinued, the Sears clerk directed to the 33392 Universal Fuel filter with my motor size listed right on the packaging.

    My engine starvation problem started right after I changed the fuel filter to the Universal 33392. So I knew where to begin to look. The fuel delivery system.

      I did all the usual troubleshooting at first, checked the vents in the gas tank cap, they were clear, checked the gas line and tank, both clear of obstructions, turned the key and heard the fuel solenoid click. Everything was fine, so it had to be the filter. I exchanged it for another, same problem.

     After I blew through the new filter and felt how hard it was to do, it started to make sense to me.

    The Universal gas filter 33392 is a much better filter than the original 33940 and that is the cause of the problem.

    33940 (original filter) does well in GRAVITY FED engines, it has a filter screen that still allows for a fast fuel flow rate (easy to blow through). If your engine is without a fuel pump (gravity fed) this is an important operating characteristic!      

    The universal replacement filter 33392 has a fine fiber filter screen that may do a better job filtering the gas, but a byproduct is a SLOWER gas flow rate. In gravity fed engines like mine, this is the cause of my engine's starvation problem.


    I found a small cache of original Briggs & Stratton filters (75 microns# that look just like the part I changed out (sort of like two small opaque funnels glued together). The engine runs like a champ now. Issue resolved, it was the filter.

Small Engines (Lawn Mowers, etc.)

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David R


Small Air Cooled Engines and applications including Twin Cylinders. A specialist in the Chinese Engine-- i e LIFAN, LONCIN, ZONGSHEN, RATO, LCT, YAMAKOYO, DUCAR, GREYHOUND, (Honda Engine COPY) area. Have personally been to Chinese Engine factories several times Former Day to Day job is in application engineering of 4 cycle Engines. Evaulation, testing and failure diagnosis of Chinese Engines,Briggs and Stratton and Kohler engines daily. In other words I do this everyday.


30 Years in OPE industry. Briggs and Stratton Master Service Tech, Master Parts Pro. Former owner of OPE dealership servicing and selling Honda, MTD, Murray, Husqvarna, Toro, Lawnboy, Shindaiwa, Briggs and Stratton, Kohler, and Tecumseh. Previous job as trainer for engine manufacturer performing service training for companies like SEARS, HOME DEPOT, LOWES, TSC, etc. Instructor for Technical College.

Vo Tech Training 1981, Husqvarna Factory Training, Briggs and Stratton Factory Service School(s) Tecumseh Factory Training, Shindaiwa Factory Training, MTD, Hydrogear, Toro, Lawnboy update schools. To many to list in the past 30 years.

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