Mechanical Gas Fuel System G5.9, G8.3, G855 – Master Repair Manual 013-042   Ignition Timing

Single Fuel

TOC

 CAUTION 

To prevent possible damage to the timing light, make sure that the timing light and the battery source have the same voltage.

Connect the timing light induction pick up clamp around the spark plug secondary wire for the left bank number 1 cylinder and connect the red power lead to the positive (+) post and the black lead to the negative (-) post on the battery.

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Start the engine and allow it to reach 60°C [140°F] coolant temperature.

Once up to temperature, set the engine rpm at rated speed.

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Point the timing light toward the ignition timing marks on the accessory drive pulley. The timing mark will be illuminated showing the number of degrees before top dead center (BTDC) that the spark is occurring on the cylinder to which the timing light is connected.

Compare the measured ignition timing to the specified ignition timing value for the engine.

Refer to Procedure 018-016 in Section V for the specified ignition timing values.

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Electro-Mechanical Type


If the ignition timing requires adjustment, loosen but do not remove the two mounting capscrews on the ignition generator so that the generator can be rotated.

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To advance the ignition timing, rotate the ignition generator clockwise from the rear of the engine.

To retard the ignition timing, rotate the ignition generator counterclockwise from the rear of the engine.

 
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Once the required ignition timing is achieved, tighten the two mounting capscrews.

Electro-Mechanical Ignition Generator Capscrews 47 n.m [35 ft-lb]

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Electronic Type


This procedure applies to all engines except the KTA38GC.

If the ignition timing requires adjustment, use the timing switch (1)
located under the plastic white cap at one end of the ignition generator.

 
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 CAUTION 

To reduce the possibility of shutting down or damage to the engine, do not switch from position 7 to 0 or 0 to 7 while the engine is running.

NOTE: Switch position 7 gives the most advance timing, position 9 is full retard timing.

Turn the timing switch one position at a time while observing the timing marks with the timing light until the desired timing is obtained.

To advance the timing, rotate the switch clockwise.

To retard the timing, rotate the switch counterclockwise.

 
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NOTE: KTA38GC engines use an ignition display to adjust timing.

If the ignition timing requires adjustment, press the “Timing”
button on the ignition display.

Press the “Up Arrow” button to select Global (Engine).

Press the “Up Arrow” button to select Adjust Retard.

Use the “Up Arrow” and “Down Arrow” buttons to adjust global timing until the desired timing is obtained.

 
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Bi-Fuel

TOC

 CAUTION 

To prevent possible damage to the timing light, make sure that the timing light and the battery source have the same voltage.

Connect the timing light induction pick up clamp around the spark plug secondary wire for the left bank number 1 cylinder and connect the red power lead to the positive (+) post and the black lead to the negative (-) post on the battery.

 
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Natural Gas


With the fuel supply set to natural gas, start the engine and allow it to reach 60°C [140°F] coolant temperature.

Once up to temperature, set the engine rpm at rated speed.

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Point the timing light toward the ignition timing marks on the accessory drive pulley. The timing mark will be illuminated showing the number of degrees before top dead center (BTDC) that the spark is occurring on the cylinder which the timing light is connected to.

Compare the measured ignition timing to the ignition timing value specified for the engine.

Refer to Procedure 018-016 in Section V for the specified ignition timing values.

SMALL | MEDIUM | LARGE
   

Electro-Mechanical Type


If the ignition timing requires adjustment, loosen but do not remove the two mounting capscrews on the ignition generator so the generator can be rotated.

SMALL | MEDIUM | LARGE
   


To advance the ignition timing, rotate the ignition generator clockwise from the rear of the engine.

To retard the ignition timing, rotate the ignition generator counterclockwise from the rear of the engine.

 
SMALL | MEDIUM | LARGE
   


Once the required ignition timing is achieved, tighten the two mounting capscrews.

Electro-Mechanical Ignition Generator Capscrews 47 n.m [35 ft-lb]

SMALL | MEDIUM | LARGE
   

Electronic Type


This procedure applies to all engines except the KTA38GC.

If the ignition timing requires adjustment, use the timing switch (1)
located under the plastic white cap at one end of the ignition generator.

 
SMALL | MEDIUM | LARGE
   


 CAUTION 

To reduce the possibility of shutting down or damage to the engine, do not switch from position 7 to 0 or 0 to 7 while the engine is running.

NOTE: Switch position 7 gives the most advance timing, position 9 is full retard timing.

Turn the timing switch one position at a time while observing the timing marks with the timing light until the desired timing is obtained.

To advance the timing, rotate the switch clockwise.

To retard the timing, rotate the switch counterclockwise.

 
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Propane


Turn off the natural gas supply so the engine is running on propane.

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Point the timing light toward the ignition timing marks on the accessory drive pulley. The timing mark will be illuminated showing the number of degrees before top dead center (BTDC) that the spark is occurring on the cylinder which the timing light is connected to.

Compare the measured ignition timing to the ignition timing value specified for the engine.

Refer to Procedure 018-016 in Section V for the specified ignition timing values.

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If the ignition timing requires adjustment, turn the adjustment screw until the measured ignition timing matches the specified ignition timing value for the engine.

 
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Last Modified:  26-Jun-2006