Fog1965
ArboristSite Lurker
I am in the process of rebuilding an MS290 to correct damage caused by ethanol. I have a new engine and have disassembled everything that I need to. All that is left are the four bolts that hold the engine together and to the plastic frame/chassis/crankcase (depending on where you look as to what is called). I removed one OK, one of the ones in the open on the outside. When I went to removed the second one, which is down a square hole (naturally), the head twisted off the socket and is wedged in the bolt. It is one of the torgue (sp?)/star bolts.
It appears to have been over tightened at the factory, and in checking the other two they are also over tightened. The factory specs call for 11 Newtons or 8.3 ft/lbs to tighten and I applied well over 30 ft/lbs trying to loosen then. I know that this saw has never seen a torque wrench as it went down the assembly line, most liked air drills.
So, I have two problems. The first is the broken part of the socket imbedded in the screw. I have managed to drill out part of it, but so far have not been able to clear the remainder. I am getting close to just drilling the head off the bolt so I can pull it through the frame/chassis/crankcase - and then tackle the other two. If anyone has some experience with this problem, I will be most interested.
The second problem I am facing, is if I do wind up having to drill the head off the bolt then I have to remove the bar stud that threads into the engine. I checked with Stihl on the "special tool" that they have to remove it and was quoted a price of $82-$84 for it. With a number of people having rebuilt these, what is the method used to remove the bar stud without having to give Stihl another $84.
Any information and previous experience in these issues will be greatly appreciated. The patience is starting to wear thin with this thing, I am convinced that it was either built on a Friday or Monday - either getting ready for the weekend and not caring or with a hangover from the weekend and caring even less.
Thanks,
Fog
It appears to have been over tightened at the factory, and in checking the other two they are also over tightened. The factory specs call for 11 Newtons or 8.3 ft/lbs to tighten and I applied well over 30 ft/lbs trying to loosen then. I know that this saw has never seen a torque wrench as it went down the assembly line, most liked air drills.
So, I have two problems. The first is the broken part of the socket imbedded in the screw. I have managed to drill out part of it, but so far have not been able to clear the remainder. I am getting close to just drilling the head off the bolt so I can pull it through the frame/chassis/crankcase - and then tackle the other two. If anyone has some experience with this problem, I will be most interested.
The second problem I am facing, is if I do wind up having to drill the head off the bolt then I have to remove the bar stud that threads into the engine. I checked with Stihl on the "special tool" that they have to remove it and was quoted a price of $82-$84 for it. With a number of people having rebuilt these, what is the method used to remove the bar stud without having to give Stihl another $84.
Any information and previous experience in these issues will be greatly appreciated. The patience is starting to wear thin with this thing, I am convinced that it was either built on a Friday or Monday - either getting ready for the weekend and not caring or with a hangover from the weekend and caring even less.
Thanks,
Fog