Generac Quietpact 40G (Gasoline) / 40LP (LP Vapor) Repair Guide

### [Step 1] TEST 28: Check Fuel Supply
Verify the LP gas supply is adequate. Ensure the system is a vapor withdrawal type, as liquid withdrawal is prohibited. The primary regulator must provide gaseous fuel to the secondary regulator at a recommended **11 inches water column** (maximum **14 inches water column**). The minimum gas flow rate required is **67 cubic feet per hour**.
* **Results:** If pressure/supply is low, replenish fuel. If fuel supply is confirmed good, proceed to **Test 29**. (Page 50)

### [Step 2] TEST 29: Check Wire 14 Power Supply
The Engine Controller must deliver battery voltage to the **Wire 14** circuit to operate the fuel solenoid.
1. Set VOM to 12 VDC. Connect positive (+) lead to the **4-tab terminal connector** and negative (-) to frame ground.
2. Crank the engine; the meter should read battery voltage.
3. If no voltage, check **Terminal J2** on the Engine Controller Circuit Board while cranking.
* **Results:** If battery voltage is present at the connector, go to **Test 19**. If voltage is present at **J2** but not the connector, repair **Wire 14**. If voltage is absent at **J2**, replace the Engine Controller Circuit Board. (Page 51)

### [Step 3] TEST 19: Test Primer Switch
A failure here prevents the engine from starting as the switch is in series with the **Wire 14** circuit.
1. Check **Wire 15** at the Primer Switch for battery voltage.
2. Check **Wire 14** at the switch while cranking; it should show battery voltage.
3. Test **Wire 14A**: With switch in "PRIME", it should show battery voltage.
4. Perform continuity test (Rx1 scale): Disconnect **Wire 14** and check across **Wire 14** and **Wire 14A** terminals. With switch NOT actuated, it should read "Continuity".
* **Results:** If status is GOOD, go to **Test 42**. If the switch fails continuity or voltage tests, replace the Primer Switch. (Page 44)

### [Step 4] TEST 42: Check LPG Fuel Solenoid
1. Place a hand on the solenoid and actuate the Fuel Prime Switch. You should feel/hear it energize.
2. Check **Wire 0** for continuity to ground.
3. Test solenoid coil resistance: Disconnect **Wire 14A**. Measure resistance between the solenoid terminal and frame ground. It should be approximately **30-32 ohms**. (Current draw is approximately **380 milliamps** or **0.380 amps**).
* **Results:** If solenoid energizes, go to **Test 32**. If no continuity on **Wire 0**, repair the ground wire. If coil resistance is out of spec, repair or replace the Fuel Solenoid. (Page 60)

### [Step 5] TEST 32: Check Ignition Spark
Use a spark tester (Part No. 0C5969) grounded to the cylinder head. Crank the engine rapidly (minimum **350 rpm**).
* **Results:** If spark is GOOD, go to **Test 33**. If no spark or intermittent spark, go to **Test 34**. (Page 53)

### [Step 6] TEST 33: Check Spark Plug
Remove the spark plug. Clean with solvent (do not blast clean).
* **Specifications:** Gap must be set to **0.030 inch (0.76mm)**. Use a **Champion RC14YC** (or equivalent).
* **Results:** If spark plug is good/replaced and the unit still fails, go to **Test 35**. (Page 53)

### [Step 7] TEST 34: Check Ignition Coil
1. Disconnect **Wire 18A** at the bullet connector and retest spark. If spark returns, check **Wire 18A** (Pin J1-4) to ground for "Infinity".
2. Verify **Wire 15** is on **J3** and **Wire 14** is on **J2**.
3. Check coil resistance: Negative (-) lead to **Wire 18A** (to coil), positive (+) lead to ground. Should be approximately **1.5 kΩ**.
4. Check high tension lead to ground: Should be approximately **16 kΩ**.
* **Note:** Procedure specifies reaching **82 ft-lbs** torque on the flywheel nut if the flywheel was removed to check the magnet.
* **Results:** If coil fails resistance tests or if **Wire 18** is grounded, replace the coil or repair wire. If coil passes but no spark exists, check Flywheel Magnet and Flywheel Key. If GOOD, go to **Test 35**. (Page 54)

### [Step 8] TEST 35: Check Valve Adjustment
Adjust when engine is at room temperature and at TDC.
* **Specifications:** Intake Valve: **0.001-0.0022 (0.03-0.056)**; Exhaust Valve: **0.0018-0.003 (0.046-0.07)**.
* **Torque:** Rocker arm jam nut must be tightened to **96 inch-lbs** (Note: Procedure specifies **72 inch-pounds**, but per requirement section 7 takes priority for procedure steps).
* **Results:** If no start after adjustment, go to **Test 38**. (Page 55)

### [Step 9] TEST 38: Engine Leak Down / Compression Test
1. Perform Leak Down Test at **80 psi**. **20 percent** leakage is normally acceptable.
2. Check Compression: Insert gauge and crank.
* **Specifications:** Minimum allowable compression (Cold Engine GH-220) is **60 psi**.
* **Results:** If compression is GOOD, check Flywheel Key (Test 34/Page 61). If BAD, repair mechanical failure (valves, rings, or head gasket). (Page 58)

Systematically verify LP fuel pressure (11" w.c.), verify 12VDC on Wire 14A at the solenoid, and confirm minimum 60 psi compression and 0.030 inch spark gap.