Generator Maintenance & Repair Guide

When water and electricity are mixed, it is very dangerous. If you can safely approach the generator, power off the generator. If it continues to run when submerged, serious internal damage to both engine and generator will occur. If you cannot safely approach the generator or disconnect the main circuit, do not make any attempt to turn it off.

Generators can be used in various weathers and temperatures, but should be protected from short circuit and rusting. NEVER run a generator indoors.

Yes. To ensure safety, the generator must be correctly grounded. If it is not grounded, you run the risk of electric shock.

No. During the running process, the generator engine produces carbon monoxide, an odorless and colorless gas, which may cause serious illness and even death.

No. Running the generator in rain or snow will lead to short circuit.

No. Stop the engine before changing from petrol to LPG or natural gas, switching between gas fuels or returning to petrol.

With the engine stopped, apply soapy water to hose and connection points, open the gas valve slowly and watch for growing bubbles.

Yes, if you choose an electrical starting generator.

—Make sure the AC circuit breaker is in the OFF position (the switch is left down). —Open the fuel cock (in the ON position). —Set the choke lever to the CLOSE position. —Turn the engine switch to the ON position If the generator is manually started, pull the recoil starter slowly until it mesh well, and then pull it quickly. If the generator is electrically started, turn the engine switch to the START position and hold it there for 3 to 5 seconds or until the engine starts.

When you use a new remote control device, you need to learn the following operations:

(a) Turn fuel tap to the ON position.

(b) Turn the engine switch to the ON position.

(c) Press and hold the learn button on the control panel till the learning indicator on the remote controller is on. (d) Connect the electric appliance.

(e) Turn the AC circuit breaker to the ON position.

(f) Make the remote controller to aim at the generator receiving antenna, and then press and hold the START button for about 2 to 3 seconds. The generator will start immediately. The generator will supply the output power about 20 seconds later.

Yes, if your generator is to be used as a stand-by power supply in case of utility power failure.

Make the generator running firstly then a load is applied. Likewise, remove the load before shutting down the generator. Do not tamper with the engine rotating speed. The rotating speed is set before delivery.

For a cold petrol engine, the choke is normally moved to START or CLOSED to create a richer fuel mixture. After the engine starts, gradually move it toward RUN or OPEN as the engine stabilizes.

Switch off and unplug all appliances, turn the circuit breaker off, stop the engine and close the current fuel supply.

Disconnect the load, turn the breaker off and stop the engine. Close the petrol valve and LPG cylinder valve, select LPG and connect the supplied or FIRMAN-approved hose and regulator.

A qualified gas professional must first assess and install or approve the natural-gas supply. Stop the generator, close the petrol valve, select natural gas and connect the approved hose.

Stop the engine, disconnect all loads and close the current external gas valve. Disconnect the gas hose before selecting and connecting the other fuel.

A customer may connect or replace an LPG cylinder by following the WT08500 manual and local LPG rules. The engine must be stopped and the cylinder valve closed during connection.

A qualified gas professional must assess and install or approve the permanent gas supply and connection point. Once approved, the user may connect the supplied FIRMAN WT08500 hose only if the owner’s manual and local rules permit it.

Pull up the engine oil level gauge. The oil level should be in the middle of the mesh grid.

Generally, we suggest using 20w–50 oil in Africa and 10w–30 oil in cold area.

For long-term storage, please follow these guidelines.

1. Let the engine cool completely before storage.

2. Clean the generator.

- Use a wet cloth to clean the exterior surface of the generator. - Use a soft bristle brush to remove dirt and oil. - Check all air vents and cooling slots to ensure that they are clean and unobstructed. 3. Drain all fuel completely.

4. Change the oil.

5. Remove the spark plug and pour about 14 ml of oil into the cylinder. Pull the engine slowly to distribute the oil and lubricate the cylinder.

6. Reattach the spark plug.

7. Store in a clean and dry place out of direct sunlight, far away from naked flame, and with good ventilation.

Pls refer to maintenance schedule list in owner’s manual.

We suggest running the generator once a month with a load.

Adding oil inside the cylinder will prevent it from rusting. This should be done if you do not plan to use your generator for a long period.

Yes, many FIRMAN generators are built for frequent or daily use in areas with unstable grid power.

For regular operation, check the oil before each use and follow a more frequent maintenance schedule.

Hot and dusty conditions can clog the air filter and increase engine wear. Check and clean the air filter regularly, keep the generator in a shaded, well-ventilated area, and NEVER operate it in an enclosed space.

Before delivery, the generator you bought is not added with engine oil. FIRMAN generator is equipped with a low oil sensor that prevents the engine from running when there is no oil or too little oil.

Air compressors, tile saws, table saws, and industrial vacuums draw as much as 3 times the running load. For example, the average 1 HP electric motor requires about 1500 watt running load. However, during startup, the load exceeds 4500 watts, which reaches the maximum load of this generator. Whenever any extra load is added, such as the compressor starting with 80 lbs. to 100 lbs. existing air in the holding tank, the electric motor will run until fully up to its running RPM. The same holds true with a circular saw that is cutting through a large piece of wood. As the voltage drops, it is possible for the amperage to increase till exceeding the circuit breaker load.

When no electricity is generated from the socket:

(a) Check and make sure the AC circuit breaker is in the ON position.

(b) Check whether the AC connector is loose.

(c) Check whether the capacitance or AVR is damaged

(d) Check whether the alternator brush is damaged.

If your generator has been left unused for a long time, it may be hard to start. Try the following easy steps before asking for help:

1. Check the oil level.

2. Replace old fuel.

3. Change the spark plug.

4. Make sure that fuel tap is open.

5. Check all generator parts for integrity.

6. Clean the carburetor (see the engine manual).

For a FIRMAN portable generator that will not start, disconnect all appliances and turn the generator circuit breaker off. Place the generator on a level outdoor surface, then use this basic FIRMAN generator maintenance checklist:

• The fuel level and fuel valve

• The engine switch

• The engine-oil level

• The battery and terminals on electric-start models

• The choke position on petrol models

• The starting procedure in the owner’s manual

If the FIRMAN generator still does not start, contact the selling distributor or use FIRMAN After-Sales Service to find support; the Contact Us page is also available for further assistance. Do not dismantle the carburetor, fuel-injection system or internal wiring yourself.

A FIRMAN portable generator may stop, surge or run unevenly if the connected appliance requires more running or starting power than the generator can supply. Motors in refrigerators, air conditioners, pumps and power tools can draw several times their normal running power during startup.

Disconnect all appliances, restart the FIRMAN generator without load and reconnect appliances one at a time. If the generator becomes unstable when a particular appliance starts, reduce the connected load or use a higher-capacity model. See the FIRMAN Generator Buying Guide for sizing guidance.

Check that the circuit breaker is on and that overload protection has not activated. Inspect the extension cord, plug and appliance using another known working power source if safe.

For safe FIRMAN generator protection, stop the generator immediately, disconnect all appliances and allow it to cool. Check whether it is standing on a firm, level surface and whether any external frame fasteners, wheels or handles are visibly loose.

Do not restart the generator if you notice metallic knocking, fuel or oil leakage, smoke, damaged mounts or contact between moving parts and the frame. Arrange a professional inspection.

Yes. On a FIRMAN petrol generator, a low-oil protection system may prevent the engine from starting or may stop it during operation. Check the oil on a level surface and fill only with the type and quantity specified in the FIRMAN generator manual.

A fouled, wet or damaged spark plug can also cause difficult starting. Inspect or replace it only after the engine has cooled and according to the owner’s manual. Avoid repeated starting attempts if there is a strong petrol smell.

A FIRMAN petrol generator or portable diesel generator may start and then stop because of stale or contaminated fuel, restricted fuel flow, a dirty air or fuel filter, incorrect choke use, insufficient ventilation or excessive electrical load.

Disconnect the load and complete the basic checks described in the owner’s manual. If the problem continues without any connected appliances, arrange professional fuel-system or engine inspection.

• On a FIRMAN petrol or diesel generator, black smoke may indicate overloading, restricted airflow or excessive fuel.

• Blue smoke can indicate excess engine oil or oil entering the combustion chamber.

• White smoke may occur briefly during a cold start but can also indicate a fuel or engine problem if it continues.

• Stop the generator if the smoke is heavy, persistent or accompanied by loss of power, unusual noise, overheating or leakage.

If a FIRMAN portable diesel generator cranks but will not start, check that there is clean diesel in the tank, the fuel valve is open, the battery is adequately charged and the air and fuel filters are not visibly restricted. Water or contamination in diesel fuel can also prevent starting.

Do not loosen high-pressure injection pipes or dismantle the injection system. If the basic checks do not solve the problem, contact an authorized diesel service technician.

A FIRMAN generator may overheat, run roughly or lose power because of overloading, blocked cooling-air openings, low or incorrect engine oil, dirty filters, poor-quality fuel or operation in a hot or dusty environment.

Stop the generator, disconnect the load and allow it to cool. Clean only the external ventilation areas specified in the manual and reduce the load before restarting. Persistent overheating or power loss requires professional inspection.

Yes. Poor quality or contaminated fuel can cause starting problems and engine damage over time. Always use clean fuel from a reliable source, and avoid storing fuel for long periods without a stabilizer.

You can get the suggestion from the distributor when purchasing a generator. The distributor can analyze the electrical load of your house and specify and install the generator system for you.

A: Prepare the following information: — Model number — Serial number — Proof of purchase — Date and place of purchase Our technicians will guide you to complete some basic diagnoses.

Add the running watts of all appliances that may operate together, then include the highest additional starting requirement from appliances with motors or compressors and allow a reasonable reserve.

Running watts are the power an appliance uses during normal operation. Starting watts are the temporary additional power required when a motor or compressor starts.

Kilowatts measure usable real power, while kilovolt-amperes measure apparent power. The relationship is kW = kVA × power factor.

Add the rated power of the lights, television and fans, then include the refrigerator compressor’s starting requirement.

Add the running watts of both appliances and allow for the larger compressor starting surge. Requirements vary greatly with air-conditioner capacity and compressor type.

Whole-home sizing requires a load survey covering lighting, refrigeration, pumps, air conditioning, cooking equipment and other simultaneous loads.

For lighting, charging and small appliances, the SPS2000i provides 1.6kW rated inverter output. Where an RV air conditioner or several appliances are required, the 3.5kW FIG5880 may provide more capacity.

A small shop or office with lights, computers and fans may suit the SPG3000 or FIG5880 after a load calculation.

List the running and starting power of all tools that may operate together. Grinders, saws, compressors, pumps and welders can have high demands.

Petrol generators are often suitable for portable and intermittent backup. Diesel generators are commonly selected for frequent operation and commercial applications.

For the generator products covered by this FAQ, the standard warranty period is one year from the date of manufacture.

The one-year generator warranty begins from the manufacturing date recorded for the product.

The warranty covers eligible defects in materials or workmanship identified during normal use within the applicable warranty period.

The warranty normally excludes normal wear and routine maintenance items; damage caused by incorrect fuel, oil or maintenance; overloading or misuse; improper storage, accidents or corrosion; unauthorized…

First contact the distributor that sold the generator. The local distributor normally handles initial inspection, warranty processing and repair coordination.

Provide the selling distributor with the generator model, serial number, a clear photograph of the complete nameplate, proof of purchase if available, a description of the problem, supporting photographs or…

The customer is responsible for transporting or delivering the generator to the distributor or designated repair location unless the distributor agrees to another arrangement.

Yes. Distributors and authorized service centres may provide paid inspection, repair and replacement parts after the warranty period, subject to local service and parts availability.

Visit https://www.sumecfirman.com/manual-downloads and select the available owner’s manual. Save the PDF to your phone or computer so it remains available when an internet connection is unavailable.

The general downloadable owner’s manual is intended primarily for small FIRMAN petrol generators.

There is no single best fuel. Petrol is widely available and suitable for portable intermittent use.

Petrol generators are widely available in portable sizes and are often lighter and less expensive than comparable diesel models.

FIRMAN diesel generators suit frequent use, longer operating schedules and commercial applications. Compared with petrol, LPG and natural gas, diesel is less volatile, has a higher flash point and is not stored as a pressurized gas, so it generally presents a lower immediate ignition risk during routine storage and refuelling. Diesel remains combustible and still requires safe handling.

LPG can remain stored in an approved cylinder without the deterioration associated with petrol and may leave fewer liquid-fuel deposits.

Natural gas can provide convenient extended operation where an approved pipeline supply is available and avoids petrol refilling or LPG-cylinder replacement.

No. The FIRMAN WT08500 is rated at 6.85kW starting and 5.50kW running on petrol, 6.25kW starting and 5.00kW running on LPG, and 5.60kW starting and 4.50kW running on natural gas.

The answer depends on local fuel prices, generator load, operating hours and the supply method. Estimate fuel cost per hour by multiplying fuel consumed per hour by the local fuel price.

Petrol is often convenient for occasional portable home backup. Diesel may suit frequent or longer operating schedules, especially for commercial applications.

The WT08500 can operate on petrol, LPG or natural gas. Use only one fuel source at a time.

Yes. Rated running output is 5.50kW on petrol, 5.00kW on LPG and 4.50kW on natural gas.

For generator service and repairs beyond basic troubleshooting, contact an authorized FIRMAN service center. Have your model number, serial number, and proof of purchase ready — our technicians will guide you through diagnosis and, if needed, arrange for service or genuine replacement parts.

Try our generator wattage calculator to find the right size for your needs.

Visit our Anti-Fake System page to verify your product.