BODY AS-OIL PUMP 1331219 - Caterpillar

Problem
On occasion, some 3456, C15, and C18 engines have been experiencing hard start issues because of loss of fuel prime. This issue has been observed occurring mainly in units that were exercised at intervals of more than one week.Solution
If the 233-6742 Check Valve Gp is installed in the secondary fuel filter base, replace with the 327-4448 Check Valve Gp .An orifice in the new 327-4448 Check Valve Gp provides the benefit of fuel flow for priming. This orifice allows for priming without having to overcome the high cracking pressure of the 233-6742 Check Valve Gp . Additionally, this orifice regulator and check valve provides an air purge mechanism, thus improving priming and starting capability. The additional step of incorporating the 447-1817 Check Valve and 443-6656 Check Valve is needed to prevent loss of fuel prime.Perform the following procedure for the installation of the check valves. Table 1 contains the part numbers needed for this change. Some parts listed in Table 1 may not be needed if the parts were previously installed.Note: Ensure that health and safety requirements are adhered to at all times.
Table 1
Item    Qty    Part Number    Part Description    
1     1     6K-9194     Flared Elbow    
2     1     214-7568     O-Ring Seal    
3     1     447-1817     Check Valve    
4     1     327-4448     Check Valve Gp    
5     1     443-6656     Check Valve    
6     1     137-5541     Fuel Priming Pump Gp    
7     1     195-1068     Fuel Filter Base As    
8     1     326-1641     Water Separator and Fuel Filter As    
9     1     343-5527     Bowl    
10     1     6V-3683     O-Ring Seal    
Lock Out and Tag Out generator is applicable. Use the following procedure to isolate the generator set before starting any work on the unit.
Open the generator set breaker.
Put the 4-position start switch "ESC" into the OFF position on "EMCP2" or push the "Stop" button on the "EMCP3".
Activate the emergency stop.
Isolate the AC auxiliary voltage for battery chargers, coolant heaters, generator space heaters, and disconnect the battery cable.
Illustration 1 g03506445
Remove the 233-6742 Check Valve Gp and replace with check valve group (4). Torque the check valve to 28 3 N m (21 2 lb ft).
Install check valve (3) at the fuel return port of the secondary fuel filter. Install o-ring seal (2) on the male end of check valve (3). Refer to Illustration 1 for location.
Remove any previous check valve installed at the tank supply.
Illustration 2 g03506476
Install check valve (5) after the primary fuel filter, refer to Illustration 2. Torque check valve (5) to 58 5 N m (43 4 lb ft).Note: Since the check valve will be installed in the field, the risk of contamination will exist. Contamination can affect proper operation of the check valve.
Verify that the check valves