Echo PB 251 won't run. replaced plug, gas, fuel filter, air filter. took carb a part, and cleaned with carb cleaner, used the compressed cleaner to clean out venturis/ports.

Carb or filter
. replace fuel filter in tank while checking both pickup and return fuel lines.
remove carb and disassemble cleaning all parts with carb cleaner and some soft air blow . look for small screen its round and about 1/4 round in carb these are so small that the gas that's available gells and plugs the openings . try to use non-ethonal high octane gas and use echo 2cycle oil .

I'm 99.9% sure it's the fuel line. The ethnoll in gas really shrinks the oem fuel lines

loosen gas cap. Probably a bad Vent in the gas cap

Hi dbooth
Make sure your fuel lines are connected correctly.
Check the drawing below
Please rate me
Bud

I know you checked the plug, but it can fire outside the cylinder and then not fire under compression.
If you have compression, fuel, and spark at the right time you should get combustion.

when the carb was "rebuilt" Did you pull out the screen and clean it out and also did you pull needle and diaphragm out and clean it out good, because if the needle is not working or the neoprene tip is swollen your needle adjustment will be out of whack,sometimes carb cleaner will make it swell up to where it won't open enough to get fuel through it....suggest you replace the needle and adjust your height of the tab to flush with the body of carb and make sure you have a good diaphragm in it along with new check-valve diaphragm, then make sure your primer is hooked up right ..it should be pulling fuel through the filter to carb and through carb and back to tank,your problem is definitely in the fuel system, keep trying different things you will figure it out

Your description sounds like fuel restriction in the main circuit. Sometimes you need to soak the carb in carb cleaner and then blow out passageways with compressed air.

There is one "cheat" but it involves some higher throttle, and that is you remove the air filter, rev up the unit and briefly place palm over the intake. Sometimes this is enough to pull the obstruction free.

Check the exhaust port upstream from the muffler and make sure it is not restricted with carbon. Mine was less than half way covered over with carbon. Scraped out carbon, checked muffler and screen(ok), back-blow the fuel line harness including the fuel filter and fuel tank vent and took carb apart and blew out all passages, not replacing anything and now runs fine. Would not rev past high idle before. Be sure gas is FRESH and mixed at 40-50 to 1. Hope this helps.

Echo carbs have a little black plastic plug covering the High speed adj screw..CA air pulotion control bs..So get that little black blug out and give the screw a little turn open and u should be good to go..It worked for me..on a PBL 251 blower..My Echo weed wacker has the carb also..Go to Echos site and download the parts break down for your unit and look at the carb page..You will see the plug and HS,screw..happing wacking and blowing

Too much oil in gas.