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Specify a marine generator by load, cooling and installation space before you compare brand names. The unit has to fit the engine room, carry the loads you actually run at anchor, and come from a factory that can show you drawings, tolerances and test data for the batch you will receive.
Contents
- What a marine generator has to do that a regular generator does not
- Sizing: kW, the 20/20 rule and air conditioning
- Diesel or gas, and which cooling setup
- Supplier checklist: what to verify before you order
- Red flags in a marine generator quote
- Where Powerstar fits
- FAQ
- Send your load list for a specification and lead time
What a marine generator has to do that a regular generator does not
A marine generator is built for a wet, enclosed, moving environment, so ignition-protected electrical parts, marine-grade cooling and corrosion-resistant hardware are the baseline rather than extras.
Cooling is the main difference. A marine diesel generator uses raw-water or keel cooling instead of an open radiator, because engine-room air is limited and salt water is present. The set also runs while the main engines are off, at anchor or when shore power fails, so it has to hold voltage and frequency steady on its own.
Space and weight decide more purchases than output does. A compact marine genset that fits the engine room often settles the choice before the kW rating is discussed. On yachts and workboats, a soundproof enclosure belongs in the specification from the start, not added after the unit arrives.
- Ignition-protected electricals and corrosion-resistant hardware as standard
- Raw-water or keel cooling instead of a radiator
- Stable voltage and frequency when running alone
- Compact footprint and soundproof enclosure
We build soundproof and compact marine gensets for yacht, workboat and USV installations.
Sizing: kW, the 20/20 rule and air conditioning
Write out every load you expect to run at once: air conditioning, refrigeration, watermaker, battery charger, galley equipment and electronics. Add them, then add a margin for startup surge.
The 20/20 rule is a common rule of thumb for matching a marine generator to its load. Ask your supplier how they apply it to your load list, and treat their answer as a starting point, not a substitute for a full load list.
Air conditioning is the load that most often forces a step-up in size. Check the locked-rotor current of each compressor, because starting surge can be several times running current.
Small boats usually land in the 5kW to 8kW marine generator range; larger yachts and workboats move to 12kW and above.
Choose the frame size that leaves room for future loads, and match frequency to your market: 50Hz for Europe and much of the world, 60Hz for North America. Our range includes 5kW, 8kW and 12kW marine generators in 50Hz and 60Hz.
Diesel or gas, and which cooling setup
Diesel is the standard choice for marine diesel generators: better fuel economy at load, safer fuel handling on board and longer run times. Gas generators exist for small boats, but fuel storage and ventilation requirements make them a narrower choice.
| Decision | Option | Best for |
|---|---|---|
| Fuel | Diesel | Most yachts, workboats and USVs |
| Fuel | Gas | Small boats with simple electrical loads |
| Cooling | Raw-water | Compact engine rooms, common installations |
| Cooling | Keel cooling | Hulls where seawater stays out of the engine |
| Engine | 6-cylinder | Smoother running and more headroom at higher outputs |
Confirm the control panel, voltage regulation and protection features you need, then put them in the specification so the factory builds to them. We manufacture diesel marine genets and permanent magnet generators, including 6-cylinder marine generator configurations.
Supplier checklist: what to verify before you order
Ask for the drawing package first: mounting dimensions, connection points, tolerances and weight. A supplier who cannot send drawings before quoting is a risk. Then request an inspection report and test data for the batch, not just a sample unit.
- Confirm consistency from batch to batch if you build the generator into your own product: same mounting, same wiring, same panel.
- Ask about annual supply capacity and lead time in writing, and agree Incoterms (FOB, CIF or DDP) before the order.
- For OEM work, follow the process: drawings or samples, prototype, your approval, then mass production with your branding and packaging.
- Agree warranty and after-sales terms in the contract, and ask who handles spare parts and service in your market.
We manufacture to your drawings or samples, prototype for approval, then run mass production under your brand. We supply equipment manufacturers globally, factory-direct from China, with warranty and after-sales support.
Red flags in a marine generator quote
A quote with no drawings, no tolerances and no inspection report is only a price, and you cannot plan a build around it.
- Output quoted without stating frequency, cooling method or continuous versus standby rating
- A warranty described verbally but absent from the contract
- No clear answer on lead time, MOQ or who supplies spare parts
- A price far below the market with no explanation of what was removed to reach it
- A supplier who cannot name the engine block or the control panel model
Where Powerstar fits
We are a Chinese manufacturer selling under our own Powerstar brand, factory-direct to equipment manufacturers, importers and distributors. You can specify output, frequency, cooling, enclosure, color, logo and packaging, and we build to your drawings or samples.
Trade shows are one place to inspect units and meet the team before ordering. Send your load list and installation constraints for a quote, or ask for a prototype on an OEM project. We offer customization, warranty and after-sales support.
FAQ
Who makes the best marine generator?
There is no single best maker, because the right unit depends on your load list, engine-room space and service network in your market. Compare brands on cooling method, frequency, enclosure and the drawings and test data they supply. Ask each supplier for a batch inspection report before you decide.
Does Kohler still make marine generators?
Kohler marine generators appear in current dealer listings alongside Cummins Onan, Westerbeke and Fischer Panda. Check with a dealer for that brand whether the model and parts you need are available in your market. If you need a factory-direct alternative with drawing-level control, ask us for a specification.
Why choose a Fischer Panda marine generator?
Fischer Panda positions its marine generators as compact, quiet and light, integrating into boats of all sizes. That suits tight engine rooms where space and sound matter. Whether it fits your build depends on your load list and installation, so compare its dimensions and cooling setup against your engine room.
What is the recommended service interval for a marine generator?
Service intervals depend on the engine block, running hours and duty cycle, so the manufacturer’s schedule for your specific model governs. As a working rule, check oil, coolant and raw-water strainers before each season and log running hours. Ask us for the service schedule that applies to the model you order.
Send your load list for a specification and lead time
Send your load list, frequency and installation space to [email protected] or request a quote at https://powerstarindustry.com/quote-request/, and we will come back with a specification and lead time. Include your target output, cooling preference, enclosure requirements and any OEM branding, so we can respond with the details you need. If you are weighing a prototype before a production order, say so and we will quote both stages.
Last updated: 11/05/2026
