I have a 2012 model Husqvarna 372xp (completely stock) that I bought from a neighbor lady whose husband died in a car accident last fall and she was selling all his tools in preparation to move to a condo. I know he took good care of his equipment (all his fuel had Sta-bil in it and he used the saw last September so fuel should not be stale) - the backback blower and weed whip I bought from her are also Husqvarna about the same age and run flawless - the 372xp does not want to run for me - it sounds like the kill switch is on as there is no life when I pull the recoil, just a dead "chug". If I remove the sparkplug and lay the plug on the jug I have a good spark, but when it is in the cylinder it acts like there is no spark. I am getting plenty of fuel (plug is wet when pulled out - I even tried a little carb cleaner in the spark plug hole in case the fuel was poor and it was still dead - no pop, no nothing! I did a compression test for curiosity and that showed 130 lbs with relief valve closed or 90 lbs if pressure relief valve pushed in so I have good compression. Any suggestions on what I can do to get it to run?

I have a Simplicity tractor with a Briggs Vanguard 16 HP twin cylinder engine. This rig is about 16 years old; the engine has about 500 hours on it. Today the engine died on me. I noticed the fuel filter (which is clean) had very little fuel in it. In the process of cleaning out grass and debris to trace the fuel line I noticed that if I lifted up the fuel filter as much as the hoses would allow and then let it fall back into its normal position gas would dribble into filter. I was able to start the engine after doing this several times. The engine ran fine for another 10 or 15 minues until I was finished mowing. Some time did elapse between the engine conking out and me getting it started again so it did have a chance to cool somewhat. I assume the things that could cause a fuel delivery problem include a blocked gas tank screen, an air leak in the fuel line, a clogged fuel line, or a defective fuel pump. This is a vacuum operated fuel pump. It’s mounted on one of the cylinders and operates off pulsating crankcase vacuum. Before I go checking out everything in the fuel circuit I’m wondering if there’s a “most common” failure mode, for this engine with 500 hours, I should try first.