My brother called me about his new MS250. Starts fine cold and runs fine. Shut it off and wait 20 mins and it won't start and plug is wet. He's had it back to the dealer several times and all they did was crank it till it started, told him it was flooded (duh) and sent him on his way. I've read several threads about this model having flooding problems - have there been any bona-fide problems with flooding on these and if so, has Stihl made any corrections? Unfortunately, he's in Texas and I'm in WV so I can't see it first-hand. I suggested checking the fuel tank vent and carb inlet needle. It's possible he's closing the choke instead of just setting it on high idle. Any other thoughts?
MS 250 Hot Start Problem
- Thread starter buzz sawyer
- Start date
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the tank vent is a 1 way check valve, most likely the carb needle or its spring are allowing tank pressure to push fuel into the cylinder. Crack the tank cap and refill until full to reduce pressure until he can do their job of diag on the carb or tell them the carb can be pressure tested and repaired under warranty.
Seems like it's been an issue for years for the MS250 and going back to the 025. I don't think Stihl ever took it seriously or changed much. Dealers here in Texas are not terribly knowledgeable about saws by and large. Plenty of past talk on here about it, but nothing conclusive about why. One guy said he opened up his exhaust A LOT, adjusted the carb, and never had the issue again. Relieving the tank pressure seems to help a lot of the time.I think there's just been an acceptance that they flood easily, act accordingly (no choke, relieve tank pressure, maybe hold down throttle while starting).
I kinda wonder if user or dealer feedback has any impact on design anymore at large companies. Things tend to be built on what works best in theory, and in controlled engineering test environments, but field testing and feedback seems to more and more abandoned. When I was growing up in Florida, OMC outboards had local "testers" in our area who spent every day running up and down the waterways and out in the ocean abusing the motors every way they could conceive of. Running them into sandbars, launching off huge waves. Total maniacs. It seemed like a dream job lol. I think most companies see field testers as an unnecessary expense now. Luckily the chainsaw world is full of so many brilliant tinkerers that a solution has been found for manufacturing shortcomings in nearly every saw ever produced. But the dealers are often unwilling or unable to do anything about it in new saws, cause that's just how they were made.
When hot try putting the choke on all the way then back to the run position, this will set the fast idle which might help in hot starts. Steve
I had this issue with my MS250 and I just dealt with it at the time and grabbed another saw. On a whim one day I gutted the muffler, put in a new plug, new tank vent, and rebuilt the carb. I tuned it and it's been starting like a champ ever since. Not sure which thing did it as I did them all at once but it hasn't missed a beat. When warm it starts with one light pull.
Snorty little guy for what it is as well now !!
Snorty little guy for what it is as well now !!
Yep, already told him.
Already told him that, waiting for his response.
Many thanks for the replies. I have forwarded them to him. He is writing a letter to Stihl, hopefully they will refund. If so, I recommended an Echo
My Makita 6421 I bought used does this a lot. Great saw otherwise. Never bothered to nail down why, just worked around it. But the couple of people who said gutting the muffler/opening up the exhaust helped fix their MS250 issue got me thinking the problem may well be in the restrictiveness of my cat muffler on the 6421 which the 6401 didn't have. Good chance if I gut my muffler or switch out to the old style and retune it, I may solve my issue.
spuldup
ArboristSite Operative
I don't know if this is a reference to me but I did this and it is what help my hot start problems. On a new saw I'd buy a cheap AM muffler to try first.
I also had a Warm Start problem which was resolved by cleaning the flywheel with sandpaper, but that shouldn't be needed on a new saw.
No, it was a guy from Ireland who went by WYK on a thread 12 years ago, but I think a number of people have found it helped.
Did essentially the same to mine with a few extras. I basically “back dated” my MS250. Installed the early style clamshell air filter and muffler, modified the internal baffle, converted to rim sprocket, elastostart, dual pawls in recoil, WT-215 carb, think that’s about it. Tell you what it’s an absolute ripper compared to stock. Zero starting problems hot or cold.
spuldup
ArboristSite Operative
Might you have a part number for the older air filter? Like to check that out because the stock one seems too small and plugs quickly.
Special filter kit 1123 007 1007
FYI You’ll also need the older style carb grommet and tank vent to install the older style filter. I can get part numbers here shortly.
Vent 1117 350 5800
Grommet 1123 123 7500
Grommet 1123 123 7502
Both grommets are for the WT series carbs, one is single adjust fixed high speed and the other is for double adjustment carb. Unfortunately IPL doesn’t say which is which but either one will work. Single adjust grommet can be easily modified.
Grommet 1123 123 7500
Grommet 1123 123 7502
Both grommets are for the WT series carbs, one is single adjust fixed high speed and the other is for double adjustment carb. Unfortunately IPL doesn’t say which is which but either one will work. Single adjust grommet can be easily modified.
spuldup
ArboristSite Operative
Is he mechanically competent enough to remove the carburetor and open it up or swap it then correctly adjust the new one with a little info? I have fixed a few 250's and 025s due to carb issues and its a pretty cheap fix either way...can of carb cleaner and carb kit about 20 bucks or a whole carb for about 25...Or remove the carb and then the impulse diaphragm side cover, remove the lever and needle. Using a paper Q tip with the cotton cut off twist against the needle seat to clean it, look at the needle tip for damage then wipe with microfiber towel to clean and recheck. If it looks good reuse it, I would pull the lever spring gently to very very lightly stretch it and put it all back together then run it since its a free test. I found the impulse diaphragm often got hard and rested against the lever + the lever was set a fraction too high. the carb will need to be adjusted as it will fuel a hair less with the lever not being set too high.
Those saws are little rippers once the carb is set right and the muffler is opened so it can breath and expel more heat. I still regret selling mine but I was offered a lot for it because it was a easy start. On mine I redid the carb, opened the muffler and swapped the stupid tooless bar adjuster for the side adjuster, regular clutch cover and two solid bar studs.
He is competent but doesn't want to void the warranty. The saw is only a couple weeks old. Thanks for the details.
Just in case anyone was curious, this is my “back dated” MS250 with the older style filter. You can see the tank vent and carb grommet are also the older style and must be used in order for the old filter to fit.
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