ERRATIC ENGINE OPERATION (SURGE, MISFIRING, POOR GOVERNOR REGULATION) (cont)

TM 10-3930-638-24&P

3-4. FUEL SYSTEM TROUBLESHOOTING (cont)

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

5. ERRATIC ENGINE OPERATION (SURGE, MISFIRING, POOR GOVERNOR REGULATION) (cont)

Step 16. (cont)

b. If cam roller shoes check okay, proceed to step 17.

Step 17. Check that hydraulic head screws are tight or are not missing (para 4-3b; notify general support

maintenance).

a. If hydraulic head screws are not tight or are missing, tighten and/or install (para 4-3b).

b. If hydraulic head screws are tight and not missing, proceed to step 18.

Step 18. Remove plungers and inspect for burrs, corrosion or varnishes (para 4-3b; notify general support

maintenance).

a. If plungers are burred, corroded, or varnish accumulation is present, replace (para 4-3b).

b. If plungers are okay, proceed to step 19.

Step 19. Check drive shaft tang dimension (should be not less than 0.305 inch) (para 4-3b; notify general

support maintenance).

a. If drive shaft tang measures less than 0.305 inch, replace drive shaft (para 4-3b).

b. If drive shaft tang measures more than 0.305 inch, replace head and rotor assembly (para 4-3b).

6. ENGINE IDLES IMPERFECTLY

Step 1. Check fuel injection pump timing (para 3-5a(3)).

a. If fuel injection pump timing is not correct, adjust timing as described in paragraph 3-5a(3).

b. If fuel injection pump timing is okay, proceed to step 2.

Step 2. Disassemble fuel injection pump and check transfer pump parts for wear or damage (para 4-3b; notify

general support maintenance).

a. If transfer pump parts are worn or damaged, replace (para 4-3b).

b. If transfer pump parts check okay, proceed to step 3.

Step 3. Disassemble fuel injection pump and check governor parts and linkage for wear, sticking condition,

or binding (para 4-3b; notify general support maintenance).

a. If governor parts and linkage are worn, sticking, or binding, replace (para 4-3b).

b. If governor parts and linkage are okay, proceed to step 4.

Step 4. Disassemble fuel injection pump and check governor linkage and metering valve for binding, foreign

matter and burrs; check metering valve for sticking condition (para 4-3b; notify general support

maintenance).