I play with 2-stroke engines almost every day! I own about 70 chainsaws and half of them are vintage homelites. The guy who goes by 67L36 driver is absolutely correct! Heat range plays a major role in how the saw is going to run. That plug that is too cold may have worked when the temperature was 85 and little humidity, But as I have learned through trial and error living in Portland Oregon, When it rains like hell or its 25 degrees outside, Now you're dealing with a different animal. Figure it like this guy! If a 2-stroke doesn't like burning the oil thats mixed in the fuel very easy, Then go ahead and throw in about 85-90 percent humidity on top of that and you got yourself a PIA to get things burning properly. This is how I do it and it fires up every time! Or if it starts and then dies again I can at least take compression and fire out of the list of things that will keep it from running, Because that told me that it is a fuel related issue But nine times out of ten the sparkplug is fouled! Because this is what happens. You tried to start it without success, So here comes your neighbor who thinks he can get it started, So he pulls and pulls and pulls! All this time contributing to the problem! I have a rule that it doesn't fire up after four pulls then don't pull it a fifth time. Stop, pull the plug and read what it's telling you! And there is always a couple of cry baby's that comment back, ( Oh! You can't do that! ) I'm telling you no lies! Yes you can! I take a BernsOmatic propane torch and burn the wet fuel off of the electrode staying away from the ground strap as much as possible, With the on/off switch off and choke open, pin the throttle wide open and pull the engine over about 3 or 4 times to expell the old air and fuel out of the cylinder and bringing clean oxygen in the cylinder because fire loves this stuff! Now squirt one very small shot of starting fluid in the plug hole and reinstall the hot spark plug, turn the switch back on run, pull the choke all the way out and then push it back open ever so little so that it cracks it open just enough to draw some air in. Set the saw down on the ground! Very important that you do not drop start it like most idiots do! Foot in trigger section and a good firm grip on the handle bar holding it to the ground. Now pay attention to how far your pull starter rope comes out when you pull it, You wouldn't think that it could be part of your problem but you would be wrong to think that! You need no less than 38 and no more than 41 inches of rope on your spool to get a good quality pull. I see it all the time where someone has broken the rope and never replaced it and what happens is when it comes to the end it will break the plastic pieces in the pull starter assembly! One good pull is all your gonna need and Bam!!! Old Jeds a millionaire!