Hello all, first post. I have an Echo SRM-210 trimmer that has been great for many seasons. It used to belong to my dearly departed grandfather, who worked on and repaired small engines for a good 10-15 years after retiring from the fire department. The trimmer worked fine all last season after replacing a broken recoil starter cord. Now this season the thing just refuses to start. I have tried many things, including the following: - bypassed engine stop switch, no change. - replaced dirty air filter, old spark plug, old fuel filter. - replaced torn primer bulb (wouldn't pull up any fuel) - checked for spark, there is (got shocked in the process!) - checked compression, got it up to 120 psi. - removed muffler, no visible scoring or scratching on piston - replaced fuel with fresh 93-octane mixed 1:50 with 2-cycle oil and about 1/2 ounce of Sta-bil in the 1-gallon container Echo recommends 89-octane fuel or better, but I was probably using 87 octane before now. Also the fuel sat in the tank all winter, which is why I drained it and replaced with the freshly mixed 93-octane. After many attempts to start, I noticed the spark plug is still bone dry. I don't notice any fuel smell coming from the cylinder. Could my carb be gunked up? Would one of those Zama rebuild kits be the answer? My carb says Zama RB 5 on it. Any suggestions would be much appreciated!