Carburetor float defective.
Carburetor diaphragm defective.
Lack of damping oil in carburetor.
Throttle does not open fully.
Carburetors not synchronous (2-carburetor
system).
Adjust carburetor setting.
Wrong installation of carburetor gasket (at air
filter).
Replace gasket, consider notches.
Choke engaged at warm engine.
Choke defective (worn out).
Check setting and operation of carburetor
and correct as necessary.
Operate carburetor heating system.
Induction air filter badly contaminated or
blocked.
Clean or replace air filter.
Induction system leakage.
Seal or replace induction system.
Refill fuel tank with specified fuel.
Repair or replace magneto.
Check and set magneto timing as
necessary.
Ignition switch defective.
Check grounding wire and switch and replace
as necessary.
Ignition harness loose or defective.
Fasten or replace harness.
Use specified spark plugs.