Frequently Asked Questions

This is one of the most common generator faults we see in Kenya. The engine is running normally but there is no electricity output. The cause is almost always on the electrical generation side, not the engine itself. The most frequent culprits are:

• Failed AVR (Automatic Voltage Regulator) — the single most common cause. The AVR controls the generator's output voltage. When it fails, there is typically no output at all.
• Lost residual magnetism — alternators need a small amount of residual magnetism to self-excite and begin generating power. This can be lost after a heavy fault or prolonged storage.
• Alternator winding fault — an open circuit or short circuit in the stator or rotor windings prevents power generation.
• Tripped main circuit breaker — always check this first. It is the simplest fix and is often overlooked.

Do not continue running your generator in this condition. Call us for a professional diagnosis — most AVR replacements are completed within the same day.

A generator that fails to start or cranks without firing is usually caused by one of the following:

• Dead or weak battery — the most common cause, especially for standby generators that sit idle. The battery discharges over time and cannot produce enough current to crank the engine.
• Failed starter motor — if you hear a clicking sound but the engine does not turn, the starter motor is likely failing.
• Fuel starvation — a blocked fuel filter, an airlock in the fuel line, or an empty fuel tank prevents diesel reaching the injectors.
• Low oil pressure cutout — the generator's safety system shuts it down if oil pressure drops below the safe operating threshold. Check your oil level first.
• Faulty glow plugs — diesel engines need heat to fire, especially in cold conditions. Failed glow plugs make cold starts difficult or impossible.

Regular servicing prevents most of these issues. If your generator will not start, call our 24/7 emergency line immediately.

Black exhaust smoke from a diesel generator indicates incomplete combustion — the engine is receiving too much fuel relative to the air available. Common causes include:

• Blocked or clogged air filter — very common in Kenya's dusty industrial and construction environments
• Faulty or worn fuel injectors spraying too much fuel or poor fuel atomisation
• Turbocharger failure reducing the air supply to the engine
• Generator running above its rated capacity (overloading)
• Wrong grade of diesel fuel

Persistent black smoke accelerates engine wear and increases fuel costs. Have the generator inspected promptly. Air filter replacement is a quick and low-cost fix if that is the cause.

A generator that starts but shuts down when loads are connected is usually caused by:

• Undersized generator — the generator's rated kVA is insufficient for the connected load
• High inrush current — motors, compressors, and air conditioners draw 3–6x their running current at startup, tripping overload protection
• Earth fault — a wiring fault in your installation triggering the earth leakage protection
• Voltage or frequency instability — a failing governor or AVR causing sensitive equipment to trip
• Cooling system fault — overheating triggering the engine's thermal cutout

Contact us for a full electrical and mechanical assessment. We will identify the root cause and recommend the correct solution.

Overheating is a serious fault that can cause permanent engine damage if not addressed quickly. The most common causes in Kenya are:

• Low coolant level — from a coolant leak or insufficient top-up during servicing
• Blocked or dirty radiator — dust and debris restricting airflow, very common in dusty environments
• Faulty water pump — not circulating coolant effectively through the engine
• Thermostat stuck in the closed position — preventing coolant circulation
• Poor generator room ventilation — hot exhaust air recirculating back into the radiator intake
• Running the generator significantly above its rated load for extended periods

If your generator is overheating, stop it immediately and call us. Running a hot engine causes head gasket failure, warped cylinder heads, and in severe cases total engine seizure.

Yes. Our emergency response line is open 24 hours a day, 7 days a week including public holidays. We understand that generator failures at hospitals, data centres, hotels, and industrial facilities cannot wait until morning.

Call 0722 855254 any time for emergency generator repair across Nairobi, Mombasa, and all major towns in Kenya. We will dispatch a technician to your site as quickly as possible.

We repair and service all major generator brands operating in Kenya. Our primary specialisms are Cummins and Perkins — the two most widely used diesel generator brands in Kenya. We also service:

• CAT / Caterpillar
• Volvo Penta
• FG Wilson
• Stamford and Leroy Somer alternators
• Mitsubishi, Yanmar, Deutz
• Deep Sea, ComAp, SmartGen control systems

Yes. Every repair we carry out at Steve Roberts Generators is backed by a workmanship warranty. If a fault we have repaired recurs due to our work within the warranty period, we return and fix it at no additional charge to you.

We also only use genuine OEM or certified OEM-equivalent parts — never counterfeit components — which means the parts themselves come with manufacturer quality assurance. You will receive a full service report after every job documenting exactly what was done and what parts were installed.

Service intervals depend on your generator's usage hours and operating environment. Our recommended schedule is:

• Every 250 hours or 3 months: Engine oil and oil filter change, visual inspection, battery check
• Every 500 hours or 6 months: Full service — all filters, coolant level, belts, hoses, fuel system, battery test, control panel check
• Every 1,000 hours or 12 months: Major service — everything above plus coolant flush, injector check, load bank test, and full service report
• Standby generators (rarely run): Service every 6 months regardless of hours

Kenya's dusty environment — especially in industrial areas and construction sites — means air filters often need checking more frequently than the standard intervals suggest.

Our comprehensive generator service includes:

• Engine oil drain and refill with manufacturer-specified grade
• Oil filter, fuel filter, and air filter replacement
• Coolant level check and top-up
• Radiator inspection and cleaning
• Battery condition test and terminal cleaning
• Drive belt inspection and tensioning
• Starter motor and charging alternator check
• Control panel inspection — alarms, sensors, hour meter
• Auto-start (AMF/ATS) function test
• Full load bank test to verify rated output
• Written service report issued after every visit

Yes. We offer annual Preventive Maintenance (PPM) contracts for businesses, hospitals, hotels, schools, factories, and commercial properties across Kenya. Our PPM contracts include:

• Scheduled quarterly or bi-annual service visits
• Priority 24/7 emergency response for contract clients
• Discounted spare parts pricing
• Detailed service records and equipment history
• Proactive fault identification before breakdowns occur

A PPM contract is the most cost-effective way to protect your generator investment and ensure power reliability. Contact us to discuss a contract tailored to your fleet size and location.

We come to you. All our generator services — including repair, servicing, and overhaul — are carried out on-site at your premises across Nairobi, Mombasa, and all major towns in Kenya.

Our service vehicles are fully equipped with all tools, diagnostic equipment, and common spare parts needed to complete most jobs in a single visit. You do not need to arrange any transport for your generator.

Always use the engine oil grade specified in your generator manufacturer's manual. Common grades for diesel generators in Kenya's climate are:

• Cummins engines: Typically Shell Rimula R4 15W-40 or Cummins-approved equivalent
• Perkins engines: Typically 15W-40 CF-4 or better specification
• All engines: Use API CI-4 or better rated diesel engine oil

Never mix oil grades or use petrol engine oil in a diesel generator. Using the wrong oil can void your manufacturer's warranty and cause accelerated engine wear. Our technicians always use the correct specification during servicing.

Steve Roberts Generators Company Ltd stocks and supplies genuine generator spare parts from our Kirinyaga Road, Nairobi CBD location. We specialise in Cummins and Perkins parts and carry:

• Fleetguard fuel filters, oil filters, and air filters
• Stamford, Leroy Somer, and Mecc Alte AVRs
• Deep Sea Electronics, ComAp, and SmartGen controllers
• Automatic Transfer Switch (ATS) and AMF panels
• Starter motors, water pumps, fuel injectors
• Drive belts, gaskets, and cooling system components

Same-day collection available. We also deliver to Mombasa and all major towns across Kenya. Call 0722 855254 to confirm stock and pricing.

Counterfeit generator parts are unfortunately widespread in Kenya and can cause serious engine damage while appearing identical to genuine parts. Warning signs include:

• Prices significantly below the market rate for genuine parts
• Poor quality packaging, faded printing, or missing serial numbers
• No manufacturer's hologram or authenticity label
• Seller unable to confirm the supplier or distributor chain
• Parts sourced from unlicensed street vendors or informal markets

At Steve Roberts Generators, we source all parts through authorised channels only. Every part comes with full documentation. We never supply counterfeit components — your generator and your warranty are protected.

An AVR (Automatic Voltage Regulator) is an electronic component inside the generator's alternator that controls and stabilises the output voltage. Without a working AVR, the generator cannot maintain a steady 230V or 415V output.

Signs your AVR may have failed:

• Generator runs but produces no electrical output at all
• Output voltage is much higher or lower than rated (e.g. 180V or 280V)
• Voltage fluctuates erratically causing lights to flicker
• Sensitive equipment like computers or medical devices trips or is damaged

AVR replacement is one of our most common jobs. Most replacements are completed within the same day. We stock AVRs for Stamford, Leroy Somer, and Mecc Alte alternators.

Yes. We deliver generator spare parts to Mombasa and all major towns across Kenya including Nakuru, Kisumu, Eldoret, Thika, Machakos, Meru, Nyeri, and beyond. We use reliable courier services and can also arrange delivery through our scheduled on-site service visits.

For urgent parts in Mombasa, WhatsApp us your requirement and we will advise on the fastest delivery option available. Call 0722 855254 or WhatsApp to discuss your parts requirement.

Generator sizing depends on your total connected load. The basic process is:

• List all electrical equipment you want to power simultaneously
• Note each item's wattage (from the nameplate or manual)
• Add up the total watts to get your running load
• Multiply by 1.25 to get your minimum generator size in kVA
• For motors and compressors, allow 3x their running kW for startup surge

As a rough guide for Kenya: a 3-bedroom home typically needs 5–10kVA; a small office 15–30kVA; a medium commercial building 60–150kVA; a factory or large facility 200kVA and above.

Contact us for a free professional load assessment — it takes 30 minutes and ensures you buy exactly the right size generator, not one that is too small or wastefully oversized.

An ATS (Automatic Transfer Switch) panel automatically switches your electrical load from the Kenya Power mains supply to your generator when mains power fails — and switches back when mains power returns. Without an ATS, someone has to manually operate a changeover switch every time there is a power cut.

Combined with an AMF (Automatic Mains Failure) controller, the generator also starts and stops automatically. This means your premises experience minimal downtime — typically just 10–20 seconds from power cut to generator running.

We strongly recommend ATS panels for any business that cannot afford even brief power interruptions — hospitals, data centres, hotels, manufacturing plants, and commercial offices.

Installation time depends on the size of the generator and the complexity of the electrical work required:

• Small installation (10–40kVA, home or small office): 1 to 2 days including ATS panel and changeover switch
• Medium installation (60–200kVA, commercial building): 2 to 4 days including full electrical integration and commissioning
• Large installation (250kVA+, industrial or institutional): 5 to 10 days depending on site conditions, cable runs, and panel complexity

All our installations include a final load bank commissioning test to verify that the generator performs to its rated capacity before handover.

Yes. Generator synchronization allows two or more generators to operate in parallel, combining their capacity to supply a larger load. This is ideal for facilities whose power demand exceeds the capacity of a single generator, or for critical facilities that need N+1 redundancy — meaning if one generator fails, the others continue supplying power uninterrupted.

We design, install, and commission synchronization systems using Deep Sea Electronics, ComAp, and SmartGen platforms. We serve hospitals, data centres, large hotels, factories, and telecom facilities across Kenya.

Generator repair costs in Kenya vary widely depending on the type of fault, the generator size, and the parts required. A simple fault like an AVR replacement or battery replacement is significantly less expensive than a full engine overhaul.

We always provide a clear, written, itemised quotation before any work begins. There are no hidden charges — what we quote is what you pay. Our pricing is competitive and transparent, and we will always explain exactly what is required and why before proceeding.

To get an accurate quote for your specific generator and fault, contact us with your generator brand, size in kVA, and a description of the problem.

In most cases, repairing or overhauling an existing generator is significantly more cost-effective than buying a new one — especially for large industrial generators where a new equivalent unit can cost millions of shillings.

A professionally executed engine overhaul on a Cummins or Perkins generator can extend its service life by 10–20 years at a fraction of replacement cost. We will give you an honest assessment of whether repair or replacement makes more financial sense for your specific situation. We never recommend unnecessary work.

We charge a standard callout / site visit fee for most locations within Nairobi, which covers the technician's travel and initial diagnostic time. For locations outside Nairobi, transport costs are discussed and agreed before the visit. All callout fees are clearly communicated upfront with no surprises.

For clients on annual PPM contracts, callout fees are typically waived or significantly reduced as part of the contract benefit. Contact us to discuss your location and get a clear picture of all costs before we visit.

We are based in Kirinyaga Road, Nairobi CBD and provide on-site generator services across Kenya including:

• Nairobi: All areas including Industrial Area, Westlands, Karen, Embakasi, Runda, Parklands, Eastleigh, Upperhill, South C, Thika Road
• Mombasa: Mombasa Island, Nyali, Bamburi, Likoni, Mtwapa, Diani, Kilifi, Malindi
• Central Kenya: Kiambu, Thika, Ruiru, Nakuru, Nyeri, Meru
• Western Kenya: Kisumu, Eldoret, Kakamega, Kericho
• Southern Kenya: Machakos, Kitengela, Athi River, Namanga
• Narok: Maasai Mara lodges and hotels
• North Eastern Kenya: NGOs, aid agencies, and institutions

If your location is not listed, please call us — we will find a way to reach you.

Yes. We supply locally used diesel generators that have been fully serviced, inspected, and load-tested by our technical team before sale. Our used generators range from 10kVA to 1000kVA+ and include popular brands such as Cummins, Perkins, and FG Wilson.

Every used generator we sell comes with a service report, delivery to your site, and professional installation if required. After-sales service and spare parts supply are also available.

You can reach us through any of the following:

• Phone / WhatsApp: 0722 855254 (24/7 for emergencies)
• Email: steverobertsgenerators.ltd@gmail.com
• Office: Kirinyaga Road, Nairobi CBD (24 hours, 7 days a week)
• Online form: Fill in our contact form for a written quote response

No problem at all. Our team is happy to answer any generator-related question — whether it is about a specific fault, a parts enquiry, a sizing question, or anything else. Just call, WhatsApp, or email us and we will give you a straight, honest answer.

We believe in giving people accurate information so they can make good decisions about their generators. There is never any pressure or obligation when you contact us.