TM5-6115-593-34
NAVFAC P-8-631-34
TO-35C2-3-463-2
Table 2-2. Generator Set, Troubleshooting - Continued
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
4. ENGINE RUNS ERRATICALLY OR MISFIRES
Step 1. Check fuel lines into and out of the fuel injection pump for damage, blockage, or air leaks.
Air leaks occurring at any point prior to the fuel injection pump will cause erratic engine operation. Air
leaks are difficult to detect and a trial-and-error approach may be necessary. Check for loose fittings and
defective fuel filter gaskets. Placing a fairly heavy oil around a suspected fitting may reveal the
presence of air leaks. The oil would be sucked, quite noticeably, into the fuel line if air leaks are present.
Step 2. Check the engine's exhaust ports for presence of blackish smoke (unburnt fuel).
If present, note if smoke is coming from left or right exhaust port. If the left port is the source, it may be
assumed that one of the fuel injectors or cylinders on the left side of the engine is malfunctioning.
Stop engine and remove the valve cover associated with suspected side of engine (see Chapter 13).
Restart engine. Visually inspect valves, rocker arms, and push rods for improper or misadjusted
operation.
If, for example, one push rod appears bent, the associated rocker arm will not travel as far as adjacent
rocker arms and the corresponding valve not fully open. Thus, by comparing the motion of one rocker
arm to other rocker arms, a faulty rocker arm or push rod would be immediately apparent.
Step 3. Check KW and KVAR readings on Generator Control Panel.
If readings indicate excessive power draw, rearrange load distribution to restore normal power
consumption.
If readings indicate excessive power draw, rearrange load distribution to restore normal power
consumption.
If KW and KVAR readings are normal, refer to Chapter 13 on engine assembly testing.
5. GENERATOR OUTPUT FREQUENCY INCORRECT
Step 1. Inspect motor-operated potentiometer B4 (2, figure 4-10) according to paragraph 4-21 and refer to paragraph
4-23 for testing and replacement procedures.
Step 2. Stop engine. Unplug electrical connector from top of hydraulic governor, disconnecting output of A106.
Start engine.
If generator output is at correct frequency, governor controller A106 should be tested and repaired as
required (see paragraph 4-11).
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