15MS 362, MS 362 C
Condition Cause Remedy
Engine speed drops quickly under 
load – low power
Air filter dirty Clean air filter or replace if 
necessary
Throttle shutter not opened fully Check throttle cable and rod
Tank vent faulty Replace tank vent
Fuel pickup body dirty Install new pickup body
Fuel strainer dirty Clean fuel strainer in carburetor, 
replace if necessary
Leak on fuel hose from tank to 
carburetor
Seal connections or install new fuel 
hose
Setting of high speed screw H too 
rich
Check basic carburetor setting, 
correct if necessary
Main jet bores or ports blocked Clean the carburetor
Pump diaphragm damaged or 
fatigued
Fit new pump diaphragm 
Ignition timing wrong, flywheel out 
of adjustment, key in flywheel is 
missing or has sheared off
Fit key if necessary and secure 
flywheel properly or install new 
flywheel
Engine running extremely rich, has 
no power and a very low maximum 
speed
Choke shutter does not open Check the carburetor and service 
or replace if necessary.
Engine running too rich, loss of 
power and maximum speed too low
Choke shutter does not open fully 
in full throttle position
Check the carburetor and service 
or replace if necessary.
Erratic idle – too lean Choke shutter does not close 
completely
Check the end cover with choke 
shutter and replace if necessary
Anti-vibration elements worn Replace anti-vibration elements on 
carburetor.