Section 4 — Maintenance

Air-cooled 7 kW, 12 kW and 15 kW Generators

Lead-acid batteries present a risk of fire because they generate hydrogen gas. The

following procedures are to be followed:

•DO NOT SMOKE when near the battery;

•DO NOT cause flame or spark in battery area; and

•Discharge static electricity from body before touch- ing the battery by first touching a grounded metal surface.

Be sure the AUTO/OFF/MANUAL switch is set to the OFF position before connecting the battery cables. If the switch is set to AUTO or MANUAL, the generator can crank and start as soon as the battery cables are connected.

Be sure the utility power supply is turned off and the 7.5A and 15A fuses are removed from the generator control panel, or sparking may occur at the battery posts as the cables are attached and cause an explosion.

4.8ADJUSTING GH-410/GT-990/760

VALVE CLEARANCE

After the first 6 months of operation, adjust the valve clearance in the engine.

Important: If feeling uncomfortable about doing this procedure or the proper tools are not available, please contact the Authorized Dealer for service assistance. This is a very important step to insure longest life for the engine.

To adjust valve clearance:

When valve clearance is correct, hold the pivot ball stud in place with the allen wrench and tighten the rocker arm jam nut. Tighten the jam nut to 174 in/lbs. torque. After tightening the jam nut, recheck valve clearance to make sure it did not change.

Figure 4.10 - Valve Clearance Adjustment

Rocker

Pivot BallArm

Stud

Jam Nut

Valve

Stem

•Install new valve cover gasket.

•Re-attach the valve cover. NOTE:

Start all four screws before tightening or it will not be possible to get all the screws in place. Make sure the valve cover gasket is in place.

•Re-attach the spark plug wire to the spark plug.

•On GT-990, Repeat the process for the other cylin- der.

•Make sure the engine is at room temperature.

•Make sure that the spark plug wire is removed from the spark plug and out of the way.

•Remove the four screws attaching the valve cover with a #2 or #3 phillips screwdriver.

•Make sure the piston is at Top Dead Center (TDC) of its compression stroke (both valves closed). To get the piston at TDC, remove the intake screen at the front of the engine to gain access to the flywheel nut. Use a large socket and socket wrench to rotate the nut and hence the engine. While watching the piston through the spark plug hole. The piston should move up and down. The piston is at TDC when it is up as high as it can go.

•Loosen the rocker jam nut. Use an 10mm allen wrench to turn the pivot ball stud while checking clearance between the rocker arm and the valve stem with a feeler gauge. Correct clearance is 0.002-0.004 inch (0.05-0.1 mm).

NOTE:

Hold the rocker arm jam nut in place as the pivot ball stud is turned.

4.9COOLING SYSTEM

Air inlet and outlet openings in the generator com- partment must be open and unobstructed for con- tinued proper operation. This includes such obstruc- tions as high grass, weeds, brush, leaves and snow.

Without sufficient cooling and ventilating air flow, the engine/generator quickly overheats, which causes it to quickly shut down. (See Figure 4.9 for vent loca- tions.)

Figure 4.9 – Cooling Vent Locations

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Generac Power Systems 04389-3, 04456-3, 04390-3 owner manual Valve Clearance, Cooling System
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04389-3, 04456-3, 04390-3 specifications

Generac Power Systems has established itself as a leading name in power generation equipment, and models 04389-3, 04456-3, and 04390-3 exemplify the company’s commitment to reliability and technology. These models are particularly popular among homeowners and businesses that need dependable backup power solutions.

The Generac 04389-3 is a 22 kW standby generator designed to provide seamless power during outages. It boasts a powerful 999cc engine that can handle heavy loads, making it suitable for larger homes or commercial settings. The generator features Generac’s patented True Power Technology, which ensures clean and stable power delivery, making it safe for sensitive electronics. It also comes equipped with an innovative shutdown system that prevents damage during low oil conditions and features a five-year limited warranty for added peace of mind.

Similarly, the 04456-3 model also serves as a robust standby generator, offering 24 kW of power output. This model highlights an advanced alternator that provides a reliable source of energy for running essential appliances like refrigerators, air conditioners, and heating systems. The 04456-3 includes an automatic exercise mode, allowing it to run tests periodically to ensure it’s always ready to operate when needed. Additionally, it utilizes a user-friendly digital controller that simplifies monitoring and operational management.

The Generac 04390-3 model offers a slightly lower output at 20 kW but retains high efficiency and reliability. Like its counterparts, it features an innovative design that operates quietly while delivering consistent power. This model is particularly aimed at residential users who require dependable backup solutions without the noise commonly associated with generators. It incorporates Generac’s Smart Management modules, enabling users to manage power loads effectively and avoid overloading the system.

All three models benefit from Generac’s Mobile Link technology, which enables remote monitoring via mobile devices. This feature allows users to check the status of their generators, including maintenance alerts and operational history, providing a convenient way to manage energy needs. In summary, Generac models 04389-3, 04456-3, and 04390-3 offer cutting-edge features, dependable technology, and robust capabilities, making them an ideal choice for anyone seeking reliable backup power solutions.
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