Service Manual

3-8
Table of Contents
Twin Cylinder Engine Service Manual
February 2017 - Digital Edition
TWO BARREL CARBURETOR AND FUEL SYSTEM
Items to check prior to carburetor analysis
NOTE: Items listed below are not in any particular order, one or more may apply.
Possible Cause/Issue What to Check Actions/Corrections
Contaminated Fuel Fuel tank, hoses, lter -Inspect and ush fuel system
Low/No Fuel Fuel level in tank -Add fresh fuel
Fuel Tank is not Vented Vent hose is pinched or obstructed -Inspect and reroute/replace vent
hose
Leaking Fuel Pump Fuel Pump
-Fuel Pump Test; see “Fuel Pump
Test,” chapter 3, page 3-3
Blocked Air intake Dirty air lter -Clean/replace air lter
Leaking Intake Leaky intake gaskets, air leaks
Fuel pump vacuum hose
-Inspect/replace components
Fuel Solenoid not Energized Correct voltage to solenoid, proper
grounds
-Measure voltage to solenoid, if
none measure voltage on start
solenoid and ground.
-Inspect safety system and battery
(replace as needed)
Weak Spark at Spark Plug,
Spark Timing
Ignition coils
-Ignition Coil test or OHM test; see
“Ignition Coil Test,” chapter 5,
page 5-8 or “Secondary Coil
Test,” chapter 5, page 5-9
Chassis safety system -Inspect proper grounds, replace
components
Flywheel key -Inspect ywheel key if sheared,
replace
Spark plugs -Inspect/replace as needed
Engine Controls to Carburetor Throttle cable and choke cable,
installed and adjusted correctly
-Control Plate; see “Choke Cable,”
chapter 4, page 4-5 and “Throttle
Cable,” chapter 4, page 4-6
Combustion Chamber Integrity Perform leak down test on each
cylinder
-Engine Inspection and
Reconditioning; details in chapter
8, page 8-1
Incorrect Valve Lash Measure valve clearance at all four
valves
-Engine Assembly; specications
in section 9, page 9-22
NOTE: Always have the choke fully closed for maximum fuel pump vacuum when starting and testing.