MAGNETO AIR PUMP ASSEMBLY FAILS TO PURGE SMOKE/EXHAUST GASES FROM ENGINE.

TM 3-1040-276-23

TROUBLESHOOTING (CONT)

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

6. MAGNETO AIR PUMP ASSEMBLY FAILS TO PURGE SMOKE/EXHAUST GASES FROM ENGINE.

WARNING

A hot engine may cause fuel or trapped gases to ignite. Wait till engine cools before attempting this

procedure. Make sure float bowl toggle valve is off before pulling fuel tube from metering jet. Use a

suitable authorized container for draining fuel.

Step 1. Test for faulty magneto-air check valve.

a. Pull fuel tube (1) from metering jet (2) and drain fuel into container.

b. Unscrew air pump hose (3) from flowjector (4). Remove engine head assembly (5) from

engine tube (6).

c. Disconnect ignition cable (7) from spark igniter (8).

d. Place hand in engine tube combustion chamber, pump magneto-air pump handle (9), and

check for purging air blast from pressurizing line boss (10).

Replace magneto air pump check valve (p 2-22).

e. Repeat step 1d.

If no purging air blast from pressurizing line boss, go to step 2.

f. Assemble parts in reverse order indicated on illustration.

Step 2. Purging air line tube punctured or cracked.

Report on DA Form 2404 to your supervisor.

2-12

Change 1