WILLIAMS 520 SportJet

(Rotax ACE 1630 Engine)

Technical Guide, Maintenance, and Spare Parts

The Williams SportJet 520 described in this article is a jet-propelled sports tender equipped with the BRP Rotax ACE 1630 230 HP engine. This 1,630 cc three-cylinder four-stroke engine is supercharged. With its 5.19-meter length, 7-person capacity, and 100-liter fuel tank, this configuration is recommended for yachts of 30 meters and over. The maximum speed indicated for this version is 90 km/h (56 mph).

At Rotax Tender Parts, we offer maintenance and replacement parts for the SportJet 520 and Rotax engines: filters, spark plugs, sensors, relays, fuel supply components, gaskets, and jet pump assembly parts. The presence of the supercharger must be taken into account during maintenance and diagnostics.

Find parts for your WILLIAMS SportJet 520 – Rotax 1630

• Engine parts
• Fuel supply system
• Ignition
• Sensors
• Electrical parts
• Cooling
• Oil and filters
• Gaskets and seals
• Jet pump assembly parts
• Others

Technical specifications of the Williams SportJet 520 – Rotax 1630

• Overall length: 5.19 m.
• Beam: 2.01 m.
• Dry weight: 675 kg.
• Overall height: 1.42 m.
• Height with folded windscreen: 1.13 m.
• Engine: BRP Rotax ACE 1630, three-cylinder, four-stroke.
• Displacement: 1,630 cc.
• Supercharging: Supercharger.
• Power: 230 HP.
• Propulsion: Jet drive.
• Maximum speed: 90 km/h (56 mph).
• Capacity: 7 persons.
• Fuel tank: 100 liters.
• Fuel: Gasoline.
• Recommended yacht size: 30 m and over.
• Category: SportJet.

Specifications may vary depending on the year of manufacture and equipment. For engine part identification, check the serial number of the Rotax ACE 1630 and the 230 HP supercharged configuration.

Maintenance Schedule – Williams SportJet 520 / Rotax 1630

An initial "post-break-in" service must be performed between 10 and 25 hours: oil change and oil filter replacement, hose and clamp checks, and a general inspection.

Following that, the Williams maintenance program is primarily based on three intervals: 50 hours or 1 year, 100 hours or 1 year, and 200 hours or 2 years. For operations directly related to the Rotax 1630 engine, also consult the corresponding engine manual. A dash indicates that no operation is listed in the cell of the provided table, not that maintenance is generally waived.

* For saltwater use, anti-corrosion protection of engine compartment metal components every 10 hours of use.

** The PTO sleeve and seal must be replaced at 200 hours, regardless of the number of years.

*** The exhaust system must be flushed daily after use in saltwater or polluted water.

**** The sacrificial anode must be checked every month, and every two weeks in saltwater. It must be replaced when necessary.

Supercharger: plan for an overhaul every 200 hours of use. For the operations to be performed, consult the Rotax manual corresponding to the engine serial number.

Recommended routine maintenance by Williams

In addition to the periodic table, Williams recommends in particular to:

• regularly wash the tender with fresh water to remove salt deposits;
• check the engine oil level;
• check the coolant level;
• flush the open cooling circuit;
• grease the control cables at the console and propulsion unit ends;
• check for the absence of water, oil, or fuel in the bilge;
• regularly check the condition of the anodes;
• regularly check the tube pressure.

After use in saltwater

After use at sea, flushing is particularly important. It is necessary to:

• rinse the tender with fresh water;
• perform the engine flushing procedure;
• rinse the jet pump unit and the propulsion area;
• check the intake grate;
• check the condition of the anodes;
• inspect the engine compartment;
• monitor electrical connections and any traces of corrosion.

Intensive use or use in a tropical environment may require more frequent maintenance intervals. Follow the procedure in your manual; consult our engine flushing guide as a supplement.

Common parts for the WILLIAMS SportJet 520 – Rotax 1630

OEM part numbers identify the parts replaced; they do not automatically designate original manufacturer parts.

Verify each part number with the engine catalog for your 1630 supercharged engine, particularly for gaskets, valves, stators, and internal parts. Do not substitute a 1503 part for a 1630 part based solely on the tender model name. iNR components only apply to tenders equipped with this option; the engine overhaul parts in the second table require specific validation for the installed engine configuration.

Common issues with the WILLIAMS SportJet 520 – Rotax 1630

The following symptoms may have multiple causes. These leads are intended to guide checks, without replacing a formal diagnosis or automatically justifying the replacement of a part. Work on the fuel, electrical, supercharging, and moving systems must comply with the manual and be entrusted to a professional when necessary. (FMT)

• Engine does not start: battery, voltage during cranking, battery isolator, safety lanyard, fuses, relays, fuel supply, spark plugs, ignition coils, injectors, or sensors may be involved.
• Engine misfire: methodically check ignition, fuel supply, sensors, wiring, and compression before replacing any parts.
• Lack of power: injection, ignition, cooling, electronic limitation, or jet pump may be the cause. On this 230 HP supercharged version, the diagnosis must also take the supercharger and boost circuit into account. A clogged water intake, damaged impeller, or excessive clearance can also reduce thrust.
• Error code display: the code identifies a detected anomaly but does not prove on its own that a part must be replaced.

To guide your inspections, consult our list of Williams and Rotax fault codes and our Rotax fault code guide. Stop the engine and prevent any restart before inspecting the water intake or the jet pump.

How to identify the correct part for your SportJet 520?

Send us a clear photo, the visible OEM reference, model, year, HIN, and engine serial number. Specify the 230 HP Rotax ACE 1630 engine with supercharger and the presence of the iNR option for relevant components. Do not rely solely on the SportJet 520 designation.

Identify my part from a photo.

WILLIAMS SportJet 520 Rotax 1630: Frequently Asked Questions - FAQ

• Which engine powers the Williams SportJet 520?

  The SportJet 520 of this generation is equipped with a BRP Rotax ACE 1630, a 1,630 cc three-cylinder four-stroke engine, supercharged by a compressor and developing 230 HP.

• Does the SportJet 520 have the same Rotax 1630 as other Williams tenders?

  The Rotax 1630 has been used in different configurations and power levels on several Williams Jet Tenders. Power differences from one boat to another result from ECU/ECM programming and different jet pump units. For this specific model, the engine is equipped with a supercharger allowing it to reach 230 HP.

  See our Rotax 1630 engine guide.

• What is the maximum speed of the Williams SportJet 520?

  Williams announces approximately 90 km/h (56 mph). Actual speed may vary depending on load, hull condition, navigation conditions, and the state of the propulsion system.

• What is the weight of the SportJet 520?

  Williams indicates a dry weight of 675 kg.

• How many people can the SportJet 520 carry?

  The SportJet 520 is designed for 7 people.

• What is the fuel tank capacity?

  The SportJet 520 has a tank of approximately 100 liters.

• What fuel should be used?

  The SportJet 520 runs on 98 octane unleaded or 95 / 95-E10 unleaded.

• Why won't my Williams SportJet 520 start?

  The first items to check include:

  • battery and voltage during cranking;
  • battery isolator;
  • safety lanyard;
  • fuses and relays;
  • fuel pump;
  • fuel pressure;
  • spark plugs;
  • ignition coils;
  • injectors;
  • engine sensors;
  • fault codes recorded by the ECU.

  An electronic diagnostic can prevent the unnecessary replacement of several components. (FMT)

• Why does my WILLIAMS 520 start but lack power?

  Power loss can be related to the engine or the propulsion system. Main areas to check:

  • spark plugs or coils;
  • fuel supply;
  • injectors;
  • engine sensor;
  • supercharger issues;
  • cooling issues;
  • electronic limitation due to a fault;
  • clogged water intake;
  • damaged impeller;
  • excessive clearance in the propulsion system.

  It is important to inspect the jet pump unit before concluding it is an engine problem. Stop the engine and prevent any restart before this inspection.

• Why is my SportJet 520 overheating?

  Overheating can be caused by:

  • an obstruction in the water circuit;
  • a clogged water intake;
  • poor flushing;
  • a damaged or blocked hose;
  • a cooling system issue;
  • a faulty temperature sensor.

  If a temperature alarm appears, avoid using the engine until the cause is identified. Consult our article on engine overheating.

• Should the SportJet 520 be flushed after every sea outing?

  Yes. Freshwater flushing is particularly important after use in saltwater. Williams recommends flushing the open cooling circuit and regular cleaning of the tender to remove salt deposits. Follow the procedure in the applicable manual; our engine flushing guide complements it without replacing it.

• What is the SportJet 520 carbon ring?

  The carbon ring is part of the driveshaft sealing system. Its condition and that of the rubber bellows must be monitored. Williams mandates a check by a professional every 100 hours or before the season. An anomaly in this system can cause water ingress into the engine compartment.

• Why is there water in the bilge of my SportJet 520?

  A small amount of water can have various origins, but an abnormal accumulation must be investigated. It is necessary to check:

  • the driveshaft sealing system (carbon ring, bellows...);
  • the seawater/coolant heat exchanger (ride plate);
  • hoses;
  • fittings;
  • the exhaust system;
  • the bilge pump;
  • a hole or crack in the hull.

  The presence of water should be diagnosed quickly if it reappears after every use.

• Why is my SportJet 520 cavitating during acceleration?

  A sensation of cavitation or a loss of thrust during acceleration may be linked to:

  • debris in the intake grate;
  • a damaged impeller;
  • a damaged jet pump housing.
  • incorrect clearance between the impeller and its housing;
  • deterioration of propulsion system components (see our article on wear rings);
  • air intake or water flow disturbance.

  The propulsion system must be inspected before troubleshooting engine failures. Stop the engine and prevent any restart before inspecting the intake grate and the jet pump housing.

• What oil should be used in the Rotax 1630 of the SportJet 520?

  As with most Rotax engines, use an oil that meets the specifications recommended by BRP for this engine: XPS 4T 5W-40.

  See our Rotax 1630 engine and maintenance guide.

• Which spark plugs should be used on the SportJet 520?

  The recommended spark plugs are NGK DCPR8E. Our adaptable DCPR8E compatible spark plug is perfectly suited for the Williams 520 Sport with a 1503 or 1630 engine.

• How do I identify the correct fuel pump, relay, or sensor?

  Do not rely solely on the "SportJet 520" designation. To correctly identify a part, use the following if possible:

  • the tender year;
  • the HIN number;
  • the engine serial number;
  • the reference number printed on the original part;
  • a photo of the part.

  Identify a part for your Williams SportJet 520.

• Where can I find parts for a Williams SportJet 520 Rotax 1630?

  Rotax Tender Parts offers engine parts and components for Rotax 1630 engines, notably used on Williams Jet Tenders. Find the selection in the tables of this article and consult our Rotax parts catalog. .