Originally Posted by TOOLSHACK
The carb on the SRM-261T is ADJUSTABLE !!! The adjustment screw is hidden under a "limiter cap" that is required by the EPA. The limiter cap is located inside the hole on the top of the carb... where the rotor is (part that swivels when throttle cable is pulled). If you have a GOOD dealer in your area, he should have a service bulletin that shows him (and you) how to adjust the carb. If you run 89 octane and a synthetic oil at the CORRECT mixture, keep your air filter clean, and keep debris from building up on the exterior of the carb.... you shouldn't have any problems or need any adjustments.
I did not know about this hidden jet screw. I took a look at an old trimmer that was not running due to some carb issues and got it running. Here is a link to a small video I made on how to locate that jet screw. Thanks for posting this info.
Why don't you go over the repair forum and post this utube video since
many many people are always asking about hidden needle adjustment.