DIAGNOSE ENGINE MALFUNCTIONS
NOTE: Diagnostic charts are arranged from most
probable and simplest to verify, to least likely
and more difficult to verify.
Engine Cranks But Will Not Start
Add fuel. Bleed air.
Or Hard To Start
Use correct fuel.
Water in fuel or water frozen in fuel
Drain water from fuel tank trap.
Inspect fuel filter for water. Change
Fuel filter plugged
Replace fuel filter. Bleed air clean
fuel tank strainer.
Debris in fuel
Drain fuel tank. Clean tank strainer.
Add clean fuel.
Air in fuel system
Check for bubbles in fuel filter and
tighten connections. Bleed air.
Check fuel pump pressure. See
Engine Repair chapter.
Low battery power
Charge or install new batteries.
Slow cranking speed (poor electrical
Clean and tighten battery and starter
connections. Incorrect engine oil
Wrong engine oil
Use correct oil.
Air filter plugged
Check air filter restriction indicator
and air filter elements. Clean or
Replace fuse, relay or wiring. See
Continued on next page