1997 Mercury 9.9HP Long Tiller – 4S (M16893)

1997 Mercury 9.9HP Long Tiller – 4-Stroke (M16893) is a versatile, fuel-efficient, and durable outboard motor ideal for small boats. Known for its quiet operation, clean emissions, and reliable performance, it is a solid choice for fishing, utility, and recreational boating. Below is a detailed description:

General Information

• Brand: Mercury
• Model Year: 1997
• Horsepower: 9.9 HP
• Engine Type: 4-Stroke
• Control Type: Tiller Handle
• Shaft Length: Long (20 inches)
• Fuel Delivery: Carbureted

Key Features

• Quiet Operation: The 4-stroke design ensures smooth and quiet running, making it ideal for fishing and leisure activities.
• Fuel Efficiency: Offers superior fuel economy compared to 2-stroke engines, allowing for extended trips with less fuel consumption.
• Tiller Handle Control: Integrated throttle and gear shift on the tiller handle for easy, direct control.
• Corrosion Resistance: Designed with materials and coatings to resist corrosion, suitable for both saltwater and freshwater use.
• Long Shaft Design: Perfect for deeper transoms or heavier boats, providing optimal performance in varied water conditions.

Fuel and Oil

• Fuel Type: Unleaded gasoline (minimum 87 octane).
• Oil Type: SAE 10W-30 or 10W-40 (Mercury or Quicksilver 4-stroke oil recommended).
• Fuel Tank: Typically paired with a 3–6 gallon external fuel tank.

Performance and Applications

• Top Speed: Approximately 10–15 mph, depending on boat size, weight, and load.

Applications:

• Small fishing boats
• Utility boats
• Dinghies
• Tenders
• Pontoon boat kickers

Maintenance Tips

Routine Oil Changes

• Change the engine oil every 50 hours or once per season, whichever comes first.
• Always use a Mercury OEM oil filter to ensure compatibility and performance.

Spark Plug Maintenance

• Recommended Spark Plug: NGK DPR6EA-9 or equivalent.
• Replace spark plugs annually or every 100 hours of use. Set the gap to 0.035 inches (0.9 mm).

 Cooling System Care

• Replace the water pump impeller every 2–3 years or sooner if water flow decreases.
• Flush the motor with fresh water after every use in saltwater to prevent corrosion and buildup.

 Fuel System Maintenance

• Replace the inline fuel filter annually to maintain clean fuel delivery.
• Inspect fuel lines and the primer bulb for wear or leaks.
• Use a fuel stabilizer like Quicksilver Fuel Care for long-term storage.

Lower Unit Maintenance

• Change the gearcase oil at least once a year or after every 100 hours of operation.
• Check for water contamination (milky oil) and replace seals if necessary.

Common Issues and Troubleshooting

Hard Starting

• Cause: Stale fuel, clogged carburetor, or weak spark plugs.
• Solution: Use fresh fuel, clean the carburetor, and check or replace spark plugs.

Overheating

• Cause: Worn or damaged impeller, or a clogged water intake.
• Solution: Replace the impeller and clear any debris from the intake screen.

Loss of Power

• Cause: Dirty carburetor, fouled spark plugs, or propeller damage.
• Solution: Clean the carburetor, replace spark plugs, and inspect the propeller for damage or obstructions.

Parts and Accessories

OEM Parts

• Mercury Dealers: Genuine parts are available through authorized Mercury dealers.
• Online Retailers:
  • MercuryMarine.com
  • Boats.net

Aftermarket Parts

• Sierra Marine: Offers a range of aftermarket parts like impellers, fuel filters, and ignition components.
• NGK Spark Plugs: Reliable replacement spark plugs for Mercury outboards.

Used Parts

• eBay: Search for “1997 Mercury 9.9HP 4-stroke parts” for used or refurbished components.
• Marine Salvage Yards: Often stock older parts at affordable prices.

Performance Enhancements

Propeller Upgrade:

• Upgrading to a stainless steel propeller can improve durability and overall performance.
• Select the appropriate pitch based on your boat’s weight and usage.

Fuel Optimization:

• Use ethanol-free gasoline to prevent carburetor issues.
• Add a fuel stabilizer during off-season storage to maintain fuel quality.

Periodic Decarbonization:

• Clean the combustion chambers with a decarbonizing spray to improve performance and extend engine life. 1997 Mercury 9.9HP Long Tiller – 4S (M16893)