bought new stihl farm boss last Christmas and used once to trim tree trunk burnt down from lightening. it failed to start, fuel was one third full, oil was half full, I probably pulled a hundred times w only once it started and then shut, I gave up the plan to cut a few dead trees to prepare final building site.
last Saturday, I started w checking spark plug, in garage w light off, I saw no spark plug. brand new saw, spark plug dead, by looking at the tip, almost pristine condition, no oil, no gunk, and is dry. then connect w spark plug tester, spark is visible, so no issue there.
I thought of the gas mixture may get old, it’s premix and came w the saw. bought new 91 premium gas, but could not find the stabilizer. so I did not use the new gas. upon checking, the stihl premix gas can last two years, and if unopened, 10 years.
research indicated the saw is flooded, I confirmed that after some pulls and rechecked the spark plug, it was wet. followed some methods to un-flood the engine by upside down the engine and pulled several times. no start. tried to hold the trigger and keep throttle position on 3, the same position as restarting warm engine, and then re-start, no start.
people suggested to add a little bit of gas thr after air filter. I used syringe (wine TA testing :) ) to pull an ounce of fresh gas and injected to opening behind the air filter. it seems making a little difference. I couldn’t remember. then some posting said use w40 so I sprayed a few shots to the same opening. and miracaly the saw started.
I managed to learn to release the brake while engine running high as it may damage the clutch. restart w position 3, brake on, as soon as it starts, press trigger so saw moves in idle position, release brake, press throttle, saw runs.
I let the saw running idle for good three minutes, it feels good. this is my first time succeeding in fixing a non start engine, not car, but this tiny 2 stroke engine. (I did fix my non start truck, was a nightmare).
I believe the gas sitting too long and may have blocked the air. by pulling too many times, I must have flooded the engine, w/o the right mixture of gas and air, the spark won’t light. how exactly the w40 worked this out and nothing else no brake cleaner, no engine degreaser, I do not know.
lesson learned and I saved a trip to a small engine shop.