I have both models as well, the 210 and 261
The cabs on ALL new hand held lawn maint. equip. has to conform to Californicate's emission laws new, that's why you can no longer adjust the air fuel mixture.. the screws aren't there! They adjust them at the factory and that's what you get.
Echo did have a carb problem a while back. I thought it was fixed, but I could be wrong.
If you take the carb apart, you will find a fuel inlet filter. It's a little round screen tucked in a hole and it usually fills with dirt, get the dirt out and the problem usually goes away. The reason it runs with the choke on is because it's fuel starved. By cutting off its air supply, you are evening out the fuel/air ratio and it runs...soon as you turn the choke off, it dies because it's getting way too much air for the amount of fuel it's getting.
Same thing at idle, the butterfly is closed and when you give it throttle all this air get's in, but not enough fuel.
Keep the OUTSIDE of the carb clean (w/ brake wash or carb cleaner), a clean air filter and use a better gas and this wont be such a problem.
p.s. If you haven't removed the screen from the exhaust port, you might want to do that first... that'll bog the engine bigtime if it clogs with carbon!
"A Kick In The Grass Lawn and Landscape"
2004 6 X 12 Emerson open trailer
22" Toro self propelled w.b.
2 x Echo trimers
Echo hedge trimmer
Kawasaki hedge trimmer
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