I bought an MS251CBE, Easy Start, in 2013 and it has been reliable until this year. Now, the choke lever will not go into the full choke position during the normal start sequence. If I take the cover off and push the choke rod in a bit at the carb it will go into the full choke position. Thinking that the choke rod may have deformed somehow, I replaced it. That didn't change anything. After that, because the dealer I've been going to couldn't seem to get the right carb kit in, I replaced the carb, which did nothing for the choke problem. I assume something has changed in the parts alignment in the saw but I can't figure out what it would be. Any ideas? The first picture shows the position it naturally assumes and the second shows the position at which it will go into the full choke position.
MS251c Choke Problem
- Thread starter GT52
- Start date
Help Support Arborist Forum:
SteveSr
Addicted to ArboristSite
Linkage in backwards (end for end)?
You have to squeeze the rear handle to engage the operator present lever and pull the throtle trigger to get to choke position. I don't know if all Stihl chainsaws work this way. It is a bit more involved than brand x to get the choke on. You said any ideas.
First pic is choke on
Second is choke off
Third is Pokey concerned about lever. The lever should point towards the front of the saw. Your's appears to be pointing down after the link goes through the cam.
SteveSr
Addicted to ArboristSite
See that white "hook" next to the metal choke lever? That is your throttle interlock. It will prevent the choke from engaging without opening the throttle.
SteveSr
Addicted to ArboristSite
IMHO, all Stihls operate this way. You could probably find a patent on it somewhere.
Yeah, and your rod goes through the cam as far as I have to push mine to get it to go into choke. But, both the old rod and the new rod are bent the same way, and the saw went into choke fine for more than ten years. Something changed and I don't think it has anything to do with the rod. Both rods, laid side by side are identical, and match the drawing in the parts diagram.
Selector switch worn or damaged/deflecting? rod backwards?
take the rod out and feel both carb arms for proper actuation and inspect the plastic one for flat spots, is the choke flap hitting the air filter? kill switch spring deformed? kill wire in the way under the selector switch? even a intake boot that is smashed and deformed can cause the carb to be set forward a millimeter changing that rods stroke. I'd take things off trying the choke each time something is removed or loosened to see if it is causing binding.
take the rod out and feel both carb arms for proper actuation and inspect the plastic one for flat spots, is the choke flap hitting the air filter? kill switch spring deformed? kill wire in the way under the selector switch? even a intake boot that is smashed and deformed can cause the carb to be set forward a millimeter changing that rods stroke. I'd take things off trying the choke each time something is removed or loosened to see if it is causing binding.
Which carburetor did you put in your saw? Exact model description please. Chocke lever and throttle rod were changed and can`t be combined with the older and newer version. According to your picture it seems that your carburetor has the newer chocke rod and you have the older throttle rod. That will not work. Best would be if you ask your dealer with the serial number which carb you need. I believe you need the older Walbro carburetor, because you say your saw is from 2013, but now you put the Zama carb on it. These two can`t be combined.
