Kohler APM402 User Manual

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3.6.5 Fuel Conversion Connections
To change the fuel type, change the wiring harness connections. The engine ECM has fuel tables and spark advance curves
programmed for both natural gas and LPG. Use the following fuel connection tables and wiring diagrams to determine the
applicable connections for your generator set model. Be sure to review the wiring diagram for special applications.
For typical models with PSI and GM engines, use the following:
See Figure 33 and Figure 34.
Natural Gas Operation
 Disconnect lead 65 from lead N5.
 Disconnect lead 73B from the fuel solenoid valve.
 Connect lead 73A to the fuel solenoid valve.
LPG Vapor Operation
 Disconnect lead 73A from the fuel solenoid valve.
 Connect lead 73B to the fuel solenoid valve (LPG vapor).
 Connect lead 65 to lead N5 (ground).
LPG Liquid Withdrawal Operation
 Disconnect lead 73A from the fuel solenoid valve.
 Connect lead 73B to the fuel solenoid valve (LPG liquid withdrawal).
 Connect lead 65 to lead N5 (ground).
Auto Changeover Natural Gas/LPG Vapor Operation
 Disconnect lead 65 from N5.
 Connect lead N5 to LFP2 relay common terminal.
 Connect lead 73A to the fuel solenoid valve (natural gas).
 Connect lead 73B to the fuel solenoid valve (LPG vapor).
Harness
Natural Gas
LPG Vapor
LPG Liquid
Auto Changeover
73A
QCON-7
(NG fuel solenoid valve)
not used
QCON-7
(NG fuel solenoid valve)
N5
not used
65
65
LFP2-COM
73B
not used
QCON-10 (LPG fuel solenoid valve)
65
not used
N5
N5
not used
63
LFP1-NC low fuel pressure sensor (if used)
70E2
P6- B (15 amp fuse)
Figure 33 Gaseous Fuel Electrical Connections, Typical Models with PSI or GM Engine

Kohler APM402 Specifications

General

Brand	Kohler
Model	APM402
Category	Controller
Language	English