AboutJohn C. Bridgers Sr. Expertise Small Engine Service Center Co-Owner - ATVs, Mowers, Trimmers, Snow throwers, and Many Other Small Engine Operated Equipment. I can answer questions pertaining to Most Lawn and Garden Equipment, e.g. riders, tillers, trimmers, cement mixers, chainsaws, etc. I have been repairing small engines for 34 years. Briggs & Stratton, Tecumseh, Kohler, Lawn Boy, Stihl, Poulan, Mac, and Honda; to name a few.
Experience
Past/Present clients I have worked on small air/water cooled engines for 34 Years. I performed warranty work for Lowes of Wilson and other retailers in the area. I Own a Yard Maintenance and Certified Small Engine Repair Service Center.
Question A friend gave me a nonrunning homelite 18" 2.7 in3 chainsaw that had had only 1/2 tank of unmixed gas run through it before it stopped running (Its first ever tank of gas, with no oil mixed!). Its original chain is still quite sharp. The saw then sat for three years. It definately has spark, similar to the spark from a good running 2 stroke trimmer I have. Thinking the plug might be bad I then put a plug from a known good running 2 stroke in it. I even tried starting it in the dark thinking the spark may be going elsewhere when the plug's in the motor under compression. It has consistent 95 psi compression (with a push-on type compression tester). The fuel filter is clear, no clog, I dismantled the carb and it looks pristine, no corrosion or dirt at all. I tried putting a little gas in the plug hole, I tried putting gas right through the carb with the piston at tdc so the gas would go straight into the crankcase, I even tried putting propane gas in the carb inlet. I cleaned the plug after each failed attempt, sometimes with gas wet on the plug, sometimes not. I tried starting it according to the manufacturers"easy start" procedures and then at various throttle settings. Everything I see says this motor is like new but NOTHING makes this motor even pop once. What am I missing here? Thanks.
Answer Hello Ken:
Remove the Muffler and Inspect the Cylinder and Piston. How Bad is the Scarring in the Cylinder and On the Piston. On Chainsaws, the Compression can Show Good but if there is a Large, Deep or Numerous Small Scratches in the Cylinder or the Piston; the Engine will Not Run. The Engine May Lose the Compression Just as the Piston is Reaching Full Compression and the Plug Fires because of the Scratches in the Piston and the Cylinder being Deepest at this Point. If you know how, I would suggest you Remove the Jug and Inspect it for Gouges in it. Hope this Helps. Let me know what Happens, Please. Thanks.
