Mechanical Gas Fuel System G5.9, G8.3 – 006-064   Fuel Line Seals, NG

WARNING  Natural gas is explosive and flammable. Always be sure to maintain adequate ventilation in the work area. Keep all cigarettes, flames, pilot lights, arcing equipment, and switches out of the work area and areas with shared ventilation to reduce the possibility of severe personal injury or death when working on a natural gas system.

WARNING  Natural gas is lighter than air. Check the ceiling of the area where work is to be done for any possible ignition sources.

CAUTION  To reduce the possibility of shock loading of components downstream of the supply valve, opening and closing of the gas supply valve must be done slowly.

Slowly close the manual gas shut off valve.

NOTE: The illustrations in this procedure depict the KTA19GC engine. Although the engine will possibly be different in appearance, the procedure remains the same.

NOTE: When changing the gaskets, check the sealing surfaces to make sure they are clean and damage free.

Change the following gaskets:

1. Filter to pipe
2. Flow meter (if installed)
3. Pressure regulator
4. Pipe to pipe

1. Air filter to intake horn
2. Intake horn to fuel mixer
3. Throttle plate to turbocharger inlet pipe
4. Crossover pipe to gas inlet
5. Gas inlet to aftercooler.

Remove the intake horn and fuel mixer. Discard the old gaskets.

Remove the crossover pipe and throttle plate to the aftercooler. Discard the old gaskets.

NOTE: Loosen the nuts and bolts (2) connecting the flanges and allow the gas pressure to vent prior to removing.

Remove the eight nuts and bolts (2) connecting the flanges at several locations through out the system.

Remove and discard the old gaskets (1).

Clean the flange faces and check for any signs of damage or cracking on the flange faces.

WARNING  When using solvents, acids, or alkaline materials for cleaning, follow the manufacturer’s recommendations for use. Wear goggles and protective clothing to reduce the possibility of personal injury.

WARNING  Wear appropriate eye and face protection when using compressed air. Flying debris and dirt can cause personal injury.

Using solvent, clean the throttle plate. Dry using compressed air.

Inspect the throttle plate for any signs of damage. Replace the throttle plate if damage is found.

WARNING  When using solvents, acids, or alkaline materials for cleaning, follow the manufacturer’s recommendations for use. Wear goggles and protective clothing to reduce the possibility of personal injury.

WARNING  Wear appropriate eye and face protection when using compressed air. Flying debris and dirt can cause personal injury.

Using solvent, clean the intake horn.

Inspect the inner ports of the intake horn.

If damage is found replace the intake horn.

Inspect the gasket mating surface of the intake horn to throttle plate.

If damage is found replace the intake horn.

Install a new gasket (1) and the nuts and bolts (2) for each flange gasket removed in the system.

Install new gaskets in the following:

5. Air filter to intake horn
6. Intake horn to fuel mixer
7. Fuel mixer to turbocharger inlet pipe
8. Crossover pipe to throttle plate
9. Throttle plate to aftercooler.

Tighten the capscrews.

Install the intake horn, fuel mixer and capscrews.

Install the crossover pipe, throttle plate to aftercooler and capscrews.

CAUTION  To reduce the possibility of shock loading of components downstream of the supply valve, opening and closing of the gas supply valve must be done slowly.

Slowly open the gas supply manual shut off valve.

Using a gas detector, check all flanges and fittings for leakage. If a leak is present secure the gas supply and repeat the procedure on that flange.

Using a gas detector, check the intake horn to fuel mixer gasket area’s for leakage. If a leak is present secure the gas supply and repeat the procedure for the intake horn to fuel mixer.

Using a gas detector, check the crossover pipe and throttle plate to aftercooler gasket area for leakage. If a leak is present, secure the gas supply and repeat the procedure for the crossover pipe to throttle plate.