Sthil MS181 chainsaw problem

[Moggytom]

Bought a chainsaw in 2011 Stihl MS181 14" blade. 2011   Do not use it a lot it does not have heavy work.  Always looked after it and it has always been amazing, starts fine etc.

Made a point of never lending it out to keep it in good condition and because of dangers of chainsaw, insurance, etc.

BUT lent it once to my gardeners to help cut my leylandi hedge which had become too big. since that time it just will  not start.  I have tried numerous times to no avail.

I have cleaned out fuel and put in new, checked out the chain oil, cleaned and set the chain and oiled.  

the main problem seems to be it feels like it is siezed - when I pull the starter chord it jams so I took that out and cleaned and oiled it with 3-1 oil.  It pulls no problem whatsoever when not on the machine, like new.

I cleaned and oiled, with 3in 1, oil the rotor fan and removed the spark plug to check and clean that.  (I checked it has the correct spark plug)  Not sure about the gap thought, I think that might have too big a gap as I read the gap should be 0.02 and my gap gauge only goes down to 0.04 and the gap in my spark plug is way bigger than 0.04 but I have to assume it has always been like that as I have never altered the gap myself. but have now ordered a new spark plug anyway, so not too worried about that. I have also ordered new fuel and air filters also.

Now here is the crunch.  when the spark plug is removed the rotor and piston seem to run free and easy.  and the pull chord runs perfectly free.  However when I replace the spark plug and try to pull the chord it feels like it is seized and jams up so I cannot pull the chord fully only partially and not enough to start the machine so the machine will not start.

Does anyone have any idea why this is happening and how do I solve this problem please.

[spudulike]

Try removing the plug, turn the machine so the plug hole faces downwards and pull the starter handle a few times. Make sure the choke lever is in the stop position as the fuel I expect to come out may ignite. 

It sounds like you have petrol in the bottom of the engine. Clear it, leave the plug out all night, try starting it again then get back on here if it doesn't start.

It may be worth taking the exhaust off to take a look at the piston through the exhaust port....any scoring is bad news.