Chainsaw poor running

if it starts (maybe idles) but then dies when giving it gas it sure looks like its a carb problem , most likely dirt in the high speed jet , but could be a dirty fuel filter as well and that's inside the fuel tank

sparkplugs,spark plug wire and cap and rotor,if anything the stumble is from sparkplug wires

If it stumbles at full throttle, the fast (high) idle screw is set too rich. Using your owner's manual, locate the high idle adjustment and back it off in very very small increments. Do this until the saw will run wide open without stumbling.

Clean the muffler spark arrestor screen and check the cylinder port for carbon build-up at the upper edge. Try presetting both carburetor H and L adjustments (from lightly CW stops) 1-1/2 turns CCW each. Start the engine and allow to warm up. Pull the throttle wide open and adjust H CW until the engine speed increases, but still 4-stroking. Correct setting is when the engine 4-strokes, but immediately 2-strokes when cutting. Allow to idle and adjust L for smoother running, yet allows the engine to 'follow the throttle'. Set idle speed to keep the engine running, but doesn't try to move the chain. You may have to look closer at your carburetor if the above doesn't help. Go to:
http://www.drystacked.com
for an excellent article (but poor pix) on Walbro carburetors, but related to most all 2-stroke carburetors. Hope this helps!

Jets in chainsaw may have build-up. A good build-up remover is called SeaFoam. Add this by direction to the gas. When using the SeaFoam you need to run full throttle with intermittently full choke until motor runs smooth with no choke.

Double check 2-cycle mixture. Too lean mixture in the chainsaw wont stay running.

you have on ground +

Every year the spark plug must be replaced on chainsaws for the best performance.

So your current plug is probably fouled or has an incorrect gap from last years use.

Record your chainsaw's make and model number then go to your local large hardware store and to the lawn area, they will have a replacement spark plug. And if you don't have a ratcheting socket wrench set with spark plug removal socket, this is a great time to get one. the size will be 5/8 inch.


Always use Safety glasses and ear protection.

maf sensor or fuel pressure regulator

Couple of things I would check first. Place a funnel in a can with a paper napkin covering bottom of funnel. Pour the gas from the saw into the funnel. If there is a lot of trash in there, remove the fuel line from tank. Clean the filter with carb. cleaner. Then clean the tank with carb. cleaner. If you still have problem. Replace the Air inlet tube, (clear tube with screw type device close to carb).

Fuel pump is most likely the cause. Probably just barely making the required pressure to start. Needs to maintain 60-66 psi while cranking to start.