Check for Intake / Exhaust Restriction

Intake / Exhaust Restriction

Checking for Intake Exhaust restriction is a a visual inspection to determine if an air intake or exhaust restriction is contributing to a no start or hard start condition.

If the engine does start with a high air intake or exhaust restriction, a considerable amount of black/blue smoke is produced.

Recommended Procedure:
Inspect the air cleaner inlet and ducting to assure that it is not blocked or collapsed. Inspect the air cleaner housing and filter for proper installation. Inspect the filter minder to assure intake restriction is below the red marks.

Inspect the exhaust back pressure device bellcrank during cranking and assure that it is not closing. Inspect the exhaust system for damaged or blocked pipes. When the tang is against the stop, the valve is fully open.

 Possible Causes:

  • Snow, plastic bags or other foreign material may restrict airflow at the air inlet.
  • Misrouted air cleaner ducting.
  • On engines recently repaired, rags or cap plugs may have been inadvertently left in an air inlet pipe.
  • Exhaust back pressure device may be closing during cranking or stuck closed.
  • Tailpipe or muffler may have collapsed or been damaged or the catalytic converter is clogged.

Tools Required: