Test Conditions:

• Correct starting procedure
• Fuel in tank

Valve clearance incorrect

• Adjust valves properly with engine cold.
• Warmup engine and carry out starting tests.

Engine still difficult to start

Pressure in ring main too high (mixture too rich)

• Pull vacuum hose off pressure regulator.
• Measure pressure with gauge while operating starter
  (specified value 2.5 kg/sq cm 35psi)