Ok, the Giant hasn't had a lot of time for posting recently (sorry!) but this one called to me.
Yes, the 025/Ms250s have a bad habit of being hard to start. I know this will open me up to a rash of sh&t, but that's the way it is. I'm also sorry to say that it seems to me that it is somewhat a dealer tuning problem. Dealers will always take the problem saw, unflood it, get it started and then tune the saw to start consistenly every time. The problem is, the SAW IS ALREADY WARM. Let's face it, they don't have time to let the fool thing cool off so they can see if it starts cold. The dealer, now confident that the saw is tuned, happily turns it back over to the owner, who feels silly. He even starts it, just for good measure, before he tosses it in the trunk. All is well, so now we're all set, right? Sound familiar? Now the poor deluded owner takes the saw home and tries to start it from cold, with no luck. I have heard this story a BUNCH of times now.
Here's the thing: The tune that allows the 025(MS250) to start from warm and idle nicely is NOT always the tune that allows it to start from cold. The cold start setting harder to find ... AND the saw has to be COLD every time you try to find it!! If you DO manage to bully the saw to life on a slightly "off" setting, you are now DONE trying to find the cold start setting because the saw is warm. You have to walk away before you can try again. That is my observation with this line of saws and I have one 021, two 23s, and three 025s.
What you need to do is tune the saw to start from COLD. It is a disgusting, time consuming process, but once you get it, you will like this little saw. My saws start every time, cut well, and are stone reliable now that I understand the issue.
The process:
Unflood the saw just like the dealer did. Leave the plug out and walk away for a spell, to let the saw dry out. Set the mixture settings just like it indicates on the cover. Replace plug and try to start using the Stihl recommended procedure. You have to listen hard for the pop. With the SLIGHTEST pop, take it off choke. It should now be on the high idle setting (one step up on the lever). Pull a few times, maybe up to 5 or 7. If it starts for you, great. you're there or at least very close. If it doesn't start, you flooded it. Now, some saws may be more forgiving and you still may be able to start them with some wrangling. NOT THIS SAW. This particular saw will not start no matter how many times you yank on it. Flooded is flooded and it won't start until you unflood it. Pull the plug, turn it upside down, and pull it over 10 or 15 times.. leave the plug out, go get a frosty one, and see who got kicked off the island.
Come back after a spell (an hour?) replace plug, and repeat this process AFTER READJUSTING THE IDLE MIXTURE SCREW SLIGHTLY. Your choice, richer or leaner. Yes, you are experimenting!! If you do this enough times, going through the unflooding and drying out process each time, you will soon find the idle mixture setting that will start the saw from cold... once you get this setting, REMEMBER IT. During the experimenting process, you will find that once you're headed in the right direction (leaner or richer) the saw will start to give you a clue or two...a faint pop or a near start. Once you tune it to start cold, it will start from warm or hot just fine. If you need to speed up or slow down the idle a bit, stay the bejesus away from the idle mixture screw...you worked HARD for that setting!! Just use the idle SPEED screw.
I walked Rookie1 through this with his 021 (he also was pulling his hair out) and once he got it, everything was fab. Yeah, I know, you shouldn't have to do this, and there will probably be a few Stihl fellers (sorry in advance guys) who will say that there's something really wrong with the saw if it won't start every time with the recommended procedure. I honestly don't know what to say about that, maybe it's true, or maybe it's hubris. However, that must mean there is something wrong with all three of my 025s and they all have exactly the same problem, which I've handled pretty well using the above procedure. You can too.
I think it's one of the reasons a few of the guys (Windthrown's "miserable to run" comment comes to mind) don't like these. I do understand that, but my patience was well rewarded with good, reliable starts, and nice-running saws. I've muffler modded them and they wake up very nicely. They are easy to work on, light, and they make nice, if modest, firewood saws. Having mucked around with them enough to understand them, I am a big fan of these little guys.
In my opinion, the 021 and 23 do not quite have the internal durability of the 025 (do a search on bent rods sometime, but don't show it to your mother) so you made a good choice there.
Good luck!!