DIY fix with issues
I had the stud come loose on my echo cs2511tes which was so disappointing because it is a great little saw in so many way. I took it back to where I purchased it from and they sent it back to the Australian distributor and after several weeks they gave me a new one to replace it, for which I was very grateful,
I was then very careful about being sure not to over tension the nut on the bar stud; I prune palm trees and soon after I got the replacement I was pruning the fronds off an 8m tall cocos palm and as I was getting through a cut I used the saw to deflect a frond away from me and I felt the stud may have given way. Sure enough when I got down to refuel and adjust chain tension the stud was loose and I could no longer tension bar properly. Very disappointing because the pressure I used to deflect the frond was not excessive or unreasonable in any way. I was reluctant to take it back to the store again because I was now sure that a replacement would only have the same problem, Plus it would be quicker for me to fix than wait 2 or 3 weeks for a replacement.
The stud is only threaded into plastic housing that goes into fuel tank with some plastic bracing. So I drilled into the socket that the stud came out of, all the way into the fuel tank then tapped an M8 x 1.5 thread all the way through into the tank. Then I got a hex head M8 x 1.5 bolt and threaded it into the threaded whole from the inside of the tank which some epoxy glue as sealant. I figured there is no way the hex head will pull through. There is also a locating pin/stud behind the M8 chain bar stud/bolt which I removed and drilled through to the tank and tapped 1/4" thread through to the fuel tank into which I threaded a section of threaded bar from the outside and fitted a nut on the inside of the fuel tank because I could get a hex head bolt in from the inside of the tank because too far offset from opening. I then got a 1/4" hex nut and ground it round so if fitted comfortable in the slot of the chain bar and ran that down the stud. Then I drilled a hole in the chain cover for the extra/2nd stud to go through and made up and steel reinforcing plate that screws to the chain cover, so now I have two bar studs (photo below). I also made up and fitted a wooden spacer with a 1/4" whole in it that goes between the metal plate and the plastic cover, this prevents the steel plate bending when tightening the 1/4" nut.
Works great and has been going really well for about 8 months but now I notice the studs are getting longer, they slowly pulling through the plastic and my fuel is starting to leak. When I look inside the fuel tank I see the plastic mound that held the original stud that I tapped the M8 x 1.5 thread has peeled away around the M8 hex bolt head. This bolt and the 1/4" stud are still very firm and still very effectively secure the chain bar tightly in position but I can see that I'm going to be making a few more mods in the near future to stop the M8 and 1/4" bolts from creeping through the plastic, and fix the fuel leak which will only get worse with time. I intend putting a steel plate with a 8mm and 1/4" hole inside the fuel tank to fix this.