Why won't lightweight Echo blower take full throttle?

need to clean any filters(fuel/air),mufflers,carburetor needs cleaned, gummed up from bad or old gas(get cleaner from auto parts/hardware store),check/clean spark plug(s) it won't run full out to protect engine from overheating wrecking it.

Sounds like it needs a tune up.

https://www.hunker.com/13404667/the-backpack-blower-stalls-when-the-throttle-increases

That could be from low oil in the fuel mix or from an air leak in the front side of the combustion = crank seals (unlikely) or loose bolts at the intake/carb. About anything that restricts the fuel flow or availability to the engine, to include carburetor/gas cap venting/pinched fuel line, etc.

A clogged carburetor is often caused by leaving fuel in the chainsaw for a long period of time. Over time, some of the ingredients in the fuel may evaporate, leaving b... ehind a thicker, stickier substance. This sticky fuel can clog up the carburetor and cause the chainsaw engine to stall.

https://bestleafblowercordless.com/leaf-blower-stalls-when-i-give-it-gas/