Pre-Technician Troubleshooting & First Check
Perform these checks before calling a technician to avoid unnecessary call-out fees or diagnostic scams:
Category Component Check Procedure & Diagnostics
Fuel Line Petrol (Small/Medium) Ensure fuel valve/tap is turned ON. Check for airlock or dirt in fuel filter. Bleed air from carburetor bowl screw.
Diesel (Heavy Duty) Verify fuel level in main tank. Check water separator bowl for water or sediment. Bleed air from injection pump.
Engine Oil Both Types Remove dipstick, wipe clean, and recheck level. Low oil levels trigger auto-shutoff sensors on modern engines.
Battery & Start Petrol / Small Diesel Inspect battery terminals for corrosion/loose clamps (12"V" drop stops electric start). Clean with warm water.
Industrial Diesel Check DC charger voltage (24"V" ). Check control panel (DSE/ComAp) for fault codes (e.g., E-Stop, Low Oil Pressure).
Spark / Air Petrol Generators Remove spark plug, clean carbon deposits with sandpaper, check gap, and test for spark against engine block.
Air Filter (Both) Remove air filter foam/paper element. If choked with dust, blow clean or run engine briefly without it to test choke.
Technician On-Site Checklist (Prevention of Fraud)
Part Verification: Inspect new spare parts in their original packaging before installation. Demand to retain old, replaced components.
Oil Grade Verification: Ensure the correct oil grade is used: SAE 20W-50 for petrol engines; 15W-40 Heavy Duty Diesel Oil for diesel units. Reject recycled or unbranded oil.
No Unnecessary Overhauls: If a petrol gen lacks compression, verify valve clearance adjustments (tapping) before agreeing to a costly ring replacement.
Post-Repair Load Testing: Test the generator under full load (turn on ACs/pumps while the technician is present) to confirm stability and voltage output (220"V"-240"V" ).
Generator Types & Service Charge Estimates
Common Brands in Nigeria
Petrol (1.5kVA – 10kVA): Sumec Firman, Thermocool (Haier), Elepaq, Honda, Tiger ("I pass my neighbor").
Diesel (10kVA – 1000kVA+): Mikano, FG Wilson, Perkins, Cummins, CAT, Jubaili Bros, Denyo.
Technician Labour & Service Fees (NGN)
Repair Scope Petrol Generator Fees Diesel Generator Fees
Minor Servicing (Oil, filters, spark plug/cleaning) "₦3,000 - ₦8,000" "₦25,000 - ₦60,000"
Carburetor / Fuel Injection Servicing "₦4,000 - ₦10,000" "₦35,000 - ₦80,000"
AVR / Alternator Rewinding & Repair "₦8,000 - ₦25,000" "₦60,000 - ₦200,000+"
Top Engine Overhaul (Piston rings, valves, gaskets) "₦15,000 - ₦35,000" "₦120,000 - ₦300,000"
Complete Engine Overhaul / Rebuild "₦25,000 - ₦50,000" "₦250,000 - ₦800,000+"
Estimated Replacement Part Costs (NGN)
Petrol Parts: Spark Plug ("₦1,500 - ₦3,500" ), Automatic Voltage Regulator/AVR ("₦4,500 - ₦15,000" ), Standard Carburetor ("₦10,000 - ₦25,000" ), Recoil Starter Pull Cord ("₦4,000 - ₦10,000" ).
Diesel Parts: Fuel/Oil Filters ("₦8,000 - ₦25,000" each), Fan Belt ("₦6,000 - ₦18,000" ), Starter Motor ("₦65,000 - ₦180,000" ), Injector Nozzle ("₦25,000 - ₦70,000" ).
Top Professional Generator Service Companies in Nigeria
JMG Limited: Authorized dealers and service specialists for FG Wilson and Mitsubishi diesel systems.
Mikano International Limited: Nationwide emergency maintenance, overhauls, and genuine spare parts supply.
Jubaili Bros Nigeria: Leading supplier and service provider for Perkins-powered generating sets.
Rihanco Nigeria Ltd: Lagos-based technical firm specializing in industrial diesel repairs and maintenance.
Servipower Company Ltd: Specialized in Perkins engine overhauls, electrical control panel diagnostics, and ATS maintenance.

Servicing Intervals & Required Oil
• Petrol Units (1.5kVA – 10kVA): Change engine oil every 50 to 100 running hours (or every 2–3 weeks under heavy daily use). Use SAE 20W-50 engine oil.
• Diesel Units (10kVA+): Service every 200 to 250 running hours (or every 3–6 months). Use SAE 15W-40 Heavy Duty Diesel Oil.
Parts to Replace During Service
• Every Service Cycle: Replace engine oil, clean or replace the air filter, and inspect the spark plug (petrol) or fuel/oil filters (diesel).
• Every 2nd/3rd Cycle: Replace the spark plug (petrol), replace the inline fuel filter, replace the carburetor gasket, and change the diesel water separator filter.
Placement & Safety Guidelines
• Distance from Walls: Position the generator at least 5 to 10 feet (1.5m – 3m) away from any wall, roof overhang, door, or window.
• Ventilation & Oxygen: Requires 360-degree open airflow. Exhaust fumes must point away from living spaces.
• STRICT INDOOR BAN: NEVER run a generator indoors, inside a hallway, verandah, or enclosed garage. Carbon monoxide (CO) is completely odorless, invisible, and lethal within minutes.
Expected Lifespan of Popular Nigerian Brands
Brand & Type Capacity Range Expected Engine Lifespan
Small "I Pass My Neighbor" (Tiger/Elepaq) 0.9kVA – 1.5kVA 500 – 1,200 running hours (1–2 years under daily use)
Medium Petrol (Sumec Firman, Thermocool, Elepaq) 2.5kVA – 8.5kVA 2,000 – 3,500 running hours (3–5 years with strict oil changes)
Heavy Diesel (Mikano, FG Wilson, Jubaili Bros, Perkins) 10kVA – 100kVA+ 10,000 – 20,000+ running hours (10–15+ years)