Shop by Stihl Chainsaw Parts. Cap, Lid & Cover Parts Carburetor Parts Chain & Bar Parts Engine Parts Fastener Parts. Filter Parts Hose, Tube & Fitting Parts Miscellaneous Parts Spark Plug Parts Spring Parts. Starter Parts Tool Parts Transmission, Brake & Clutch Parts. Shop by Popular Models. Stihl MS 311 Chainsaw (MS311) Parts Diagram Select a page from the Stihl MS 311 Chainsaw diagram to view the parts list and exploded view diagram. All parts that fit a MS 311 Chainsaw. Pages in this diagram. Carburetor bracket. Carburetor WTE-9.

Stihl Chainsaw Carburetor Adjustment

All Stihl chainsaws have just three carburetor adjustment screws, so fairly easy to work on when you need to a Stihl Chainsaw Carburetor adjustment.

(LA) Idle Speed screw – This controls the engine speed at idle. If set too low, the saw will die. If set too high the chain will run. This is dangerous.

Stihl Chainsaw 311y Repair Manual

(L) Low speed adjustment screw – This is the low speed jet. This is the adjustment that controls the air/fuel mixture at idle. Adjust this screw too rich and the chainsaw will blubber and die at idle speed. Adjust this screw too lean and the engine will starve. The saw will race or surge. An extremely lean adjustment will also cause the engine to die.

(H) High speed adjustment screw – This is the high speed jet. This is the adjustment that controls the air/fuel mixture at high RPMs. Adjust this screw too rich and the chainsaw will blubber, too lean and it will over rev.

Safe Basic Settings

Screws (H) & (L) – Turn the adjustment Screws (H) & (L) down onto their seats (clockwise). Back them off 1 complete turn (counter-clockwise)
Screw (LA) – Turn (LA) Idle Speed screw until the chain stops. Then turn counter-clockwise one quarter of a turn.

Fine Tuning – Screw (L)

Stihl Ms 391 Chainsaw Manual

Erratic idling behavior; poor acceleration – Idle setting too lean; turn low speed adjusting screw (L) counterclockwise until engine runs and accelerates smoothly. Readjust screw (LA).

Stihl Model 311y Chainsaw Manual

Exhaust smokes at idle speed –Idle speed setting too rich; turn low speed adjusting screw (L) clockwise until engine speed drops. Then turn screw back one quarter turn and check that engine still accelerates smoothly when you open the throttle. Readjust screw (LA).