WILLIAMS 280 MiniJet
Parts, maintenance and diagnostics for this tender
The Williams MiniJet 280 is a compact jet-powered tender, designed especially for yachts with limited storage space. It is equipped with the 60 hp BRP Rotax ACE 903 engine, a 3-cylinder 4-stroke engine. At Rotax Tender Parts, we offer maintenance and replacement parts for the Williams MiniJet 280: engine parts, filters, ignition components, sensors, relays, fuel system components, and propulsion block parts. Before placing any order, always check the OEM part number, the year of your tender, and the engine identification.
Find parts for your WILLIAMS MiniJet 280
- Engine parts
- Fuel system
- Ignition
- Sensors
- Electrical parts
- Cooling
- Oil and filters
- Gaskets and seals
- Turbine block parts
- Other
MiniJet 280 specifications
- MiniJet 280: BRP Rotax ACE 903 engine, 60 hp, 3 cylinders, 4-stroke.
- Dimensions: length 2.79 m; width 1.54 m.
- Fuel capacity: 28 liters.
- Capacity: 3 + 1 person.
- Advertised top speed: approximately 64 km/h / 40 mph.
- Advertised dry weight: approximately 227 kg.
These specifications may vary depending on the model year and equipment. Confirm them with your tender's documentation.
How often should the WILLIAMS MiniJet 280 be serviced?
First service after break-in: to be performed between 10 and 25 hours (drain and replace the oil filter, check hoses and clamps, and perform a general inspection).
Regular full service : to be performed according to the table below, provided by the manufacturer.
| Frequency | Maintenance to be performed | By |
|---|---|---|
| After every use at sea | Exhaust system flush | User |
| Every 10 hours at sea | Engine anti-corrosion protection | User |
| Every month (2 weeks at sea) | Sacrificial anode check | User / Workshop |
| 50 hours or 1 year | Oil change + oil filter + general check of the engine, fuel, cooling, electrical, steering, and propulsion | Workshop |
| 100 hours or 1 year | Oil change + filter + periodic checks + lubrication | Workshop |
| 100 hours | Replace the power take-off (PTO) boot | Workshop |
| 200 hours or 2 years | Coolant + spark plugs + in-depth checks | Workshop |
| 200 hours | PTO sleeve/seal + propeller shaft seal/sleeve | Workshop |
Common parts for the WILLIAMS MiniJet 280
Click on a thumbnail to add one unit of the product to the cart, then access the cart to complete your order. On a computer, hover over the thumbnail to display "Buy" followed by the part name. Part names and part numbers always open the product pages. OEM part numbers identify replacement parts and do not mean that every product is an OEM part.
Common issues with the WILLIAMS MiniJet 280
The symptoms below may affect several components or systems. These are possible causes, not a diagnosis or troubleshooting guide.
- The engine does not start: battery, starter relay, starter, electrical supply, wiring and connectors, fuel pump, fuel supply, or ignition components.
- Engine misfires: spark plugs, ignition coils, injectors, fuel supply, wiring, sensors, or cylinder compression.
- Lack of power: injection, ignition, air intake, engine-side cylinder compression. Foreign object in the propulsion system, damaged impeller, or damaged wear ring causing cavitation, on the jet pump housing side.
- Fault code displayed: sensors, electrical supply, wiring, connectors, or the system identified by the code. A fault code is not enough to confirm that a particular part needs to be replaced.
To learn more about fault codes, see our list of Rotax fault codes for Sea-Doo and Williams and our guide to decoding Rotax fault codes on Sea-Doo and Williams.
How to identify the right part for your MiniJet 280?
Not sure which Rotax part to choose? Send us a photo of the part and its OEM reference (Williams, Rotax, or other...). We can help you identify the right replacement part.
You can also use our automatic part recognition tool by clicking:
WILLIAMS MiniJet 280: Frequently Asked Questions - FAQ
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What engine does the Williams MiniJet 280 have?
A 3-cylinder, 4-stroke BRP Rotax ACE 903 engine, producing 60 hp on the Williams MiniJet 280 described in this article.
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Where can I find the serial number of the Williams MiniJet 280?
The serial number (HIN) is located on the transom of the jet boat, at the top right of the propulsion system. It consists of letters and numbers, the last two of which indicate the year of the jet boat (2022 in our example below). Do not confuse the jet boat number with the engine number
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Is the MiniJet 280 engine the same as the one on the SEADOO Spark?
The Williams MiniJet 280 is equipped with the ROTAX 903 engine, just like the Sea-Doo Spark. All engine-related components are therefore common, but elements related to the transmission, propulsion system, or exhaust line may differ.
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What engine oil should I use in the MiniJet 280?
Generally, BRP XPS 4T 5W-40 synthetic oil. This oil is the same for the Rotax 1503 and the Rotax1630.
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How much oil does the MiniJet 280 require?
Approximately 3.4 to 3.6 liters depending on the exact crankcase configuration. Note that during an oil change, not all the oil can be removed, as some remains inaccessible at the bottom of the crankcase. Generally, the volume of oil that can be replaced during an oil change is between 2 and 3 liters.
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How do I properly check the oil level of the MiniJet 280?
- Start the engine and run it with an appropriate water supply if it is out of the water, or ride briefly to bring the oil up to its normal operating temperature.
- Briefly increase the RPM to around 4,000 to 4,500 RPM for about 15 seconds to ensure the oil is fluid and circulating.
- Immediately stop the engine using the start/stop button or remove the kill switch lanyard.
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Wait about 30 to 60 seconds to allow the oil to drain back into the reservoir / oil pan.
- Top up gradually only if necessary, then check the level again using the same procedure.
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What oil filter is recommended for the MiniJet 280?
Our product sheet for the 420956123 filter, pack of 4 explicitly mentions the Rotax ACE 903, and therefore the MiniJet 280. Compare the reference with your original filter; the O-ring is not included.
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What spark plugs are used on the MiniJet 280?
The Rotax 903 engine equipping the MiniJet 280 requires NGK CR8EB spark plugs. The pack of 3 compatible CR8EB spark plugs is an effective generic alternative.
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How often should the MiniJet 280 be serviced?
Generally every 50 hours or once a year. See the maintenance schedule described above.
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Why won't my MiniJet 280 start?
Possible causes include the battery, starting circuit, electrical supply, fuel supply, or ignition faults.
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Why does my MiniJet 280 start but lose power when accelerating?
The fuel supply, ignition, air intake, compression, or propulsion system may be at fault. A fault code can also electronically limit your engine and restrict its performance if the system detects a critical problem (for example, engine overheating...).
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Why is my MiniJet 280 overheating?
A problem with the cooling system circulation or an obstruction may be at fault. Avoid continuing to use it when an alert persists and have the jet boat inspected. See our article on engine overheating, checking the information specific to your model.
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Why is my Rotax MiniJet 280 running unevenly or misfiring?
The spark plugs, coils, injectors, fuel supply, sensors, wiring, or compression may be at fault. (FMT)
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What are the common issues with the MiniJet 280?
Possible symptoms include starting difficulties, misfires, power loss, overheating, and electrical faults; they do not indicate a defective part on their own.
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How do I read the fault codes of the MiniJet 280?
Use the display procedure specific to your equipment or a compatible diagnostic tool. See our fault code guide.
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What do the fault codes of the Rotax ACE 903 mean?
They identify the detected faults, not necessarily defective parts; see our list of Rotax fault codes.
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How do I know if a fuel pump or injector on the MiniJet 280 is defective?
Fuel pump: check the 12 V supply, listen for a brief hum for 2 to 3 seconds (priming), and check the fuel pump pressure (at least 56 psi). Injectors: disconnect them electrically one at a time, or carefully remove them from the engine to see if they spray when the engine is started. Caution, these operations must be carried out with all necessary precautions.
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How do I identify the right part for my MiniJet 280?
Check the OEM reference, engine version, and jet boat year; send us a photo if in doubt.
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Where can I buy replacement parts for the MiniJet 280?
Browse the products in the Rotax Tender Parts table for maintenance and replacement parts whose product sheets mention the MiniJet 280. For an original part, contact your dealer. Confirm compatibility before ordering.
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What should I check when the engine runs but the jet boat barely moves?
The impeller and wear ring may be affected, especially after sucking in a foreign object. Vibrations or unusual noise require an inspection of the propulsion system before returning it to service.
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What information should I provide to identify a part for the MiniJet 280?
A clear photo, the visible part number, the RIB model, its year, and the engine details. Use our page Identify my part from a photo.
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