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Suzuki DF9.9 / DF15 service guide

Oil, gear oil, spark plugs and the service schedule for the Suzuki DF9.9 / DF15 (9.9 to 15 hp, four-stroke), from the factory service manual, plus how we service it in Hawaiʻi.

Models covered: The 2005-on (K5) DF9.9/DF15, prefix 00992F/01502F, has different specs; see notes.

Quick answers

How much oil does a Suzuki DF9.9 / DF15 take?
1.0 L (1.1/0.9 US/Imp. qt) oil change only; 1.1 L (1.2/1.0 US/Imp. qt) with filter.
What engine oil does a Suzuki DF9.9 / DF15 use?
API SE, SF, SG, SH or SJ, SAE 10W-40.
What gear oil does a Suzuki DF9.9 / DF15 use, and how much?
Suzuki Outboard Motor Gear Oil or SAE #90 hypoid gear oil. Quantity: 170 ml (5.7/6.0 US/Imp. oz).
What spark plug does a Suzuki DF9.9 / DF15 use?
NGK DCPR6E (resistor type only), qty 2. Gap: 0.8 to 0.9 mm (0.031 to 0.035 in).
How often should a Suzuki DF9.9 / DF15 be serviced?
The factory schedule lists: Initial 20 hours; Every 50 hours (3 months); Every 100 hours (6 months); Every 200 hours (12 months). In Hawaiʻi's salt water we do a full yearly service every 200 hours or 1 year, whichever comes first, and a new engine needs its first (break-in) service.
When should the water pump impeller be replaced on a Suzuki DF9.9 / DF15?
The factory schedule says to replace it at 200 hours, and we follow that. In any case we never let it go longer than a year in Hawaiʻi's salt water.
What is the idle speed of a Suzuki DF9.9 / DF15?
1,050 to 1,150 r/min (1,100 ± 50; in gear approx. 1,000).
What is the propeller nut torque on a Suzuki DF9.9 / DF15?
18 N·m (1.8 kgf-m, 13.0 lb-ft), then the cotter pin.

Maintenance specs

Engine oilAPI SE, SF, SG, SH or SJ, SAE 10W-40
Engine oil quantity1.0 L (1.1/0.9 US/Imp. qt) oil change only; 1.1 L (1.2/1.0 US/Imp. qt) with filter
Engine oil filterCartridge under a cap held by three bolts; new O-rings.
Engine oil drain plug13 N·m (1.3 kgf-m, 9.5 lb-ft), new gasket
Gear oilSuzuki Outboard Motor Gear Oil or SAE #90 hypoid gear oil
Gear oil quantity170 ml (5.7/6.0 US/Imp. oz)
Gearcase leak test100 kPa (1.0 kgf/cm², 14.2 psi), hold 5 minutes; do not exceed 110 kPa (15.6 psi)
Spark plugNGK DCPR6E (resistor type only), qty 2
Spark plug gap0.8 to 0.9 mm (0.031 to 0.035 in)
Spark plug torque17 N·m (1.7 kgf-m, 12.5 lb-ft)
Idle speed, neutral1,050 to 1,150 r/min (1,100 ± 50; in gear approx. 1,000)
ThermostatOperating temperature 58 to 62 °C (136 to 144 °F)
Propeller nut18 N·m (1.8 kgf-m, 13.0 lb-ft), then the cotter pin
Valve clearance, coldIN 0.08 to 0.12 mm (0.003 to 0.005 in); EX 0.13 to 0.17 mm (0.005 to 0.007 in); lock nut 10 N·m (1.0 kgf-m, 7.0 lb-ft)
Timing beltInspect every 200 hours (12 months); replace every 4 years. Arrow on the belt toward the direction of rotation

Service schedule

The factory maintenance intervals, with what is replaced and what is checked at each. Rows marked Hawaiʻi are our shop's yearly service for salt water use.

  1. Initial 20 hours

    Replace: engine oil, oil filter, oil drain plug gasket, gear case oil, gear case plug gaskets, propeller cotter pin

  2. Every 50 hours (3 months)

    Replace: gear case plug gaskets

    Check: fuel filter, anodes

  3. Every 100 hours (6 months)

    Replace: engine oil, oil drain plug gasket, gear case oil, gear case plug gaskets, propeller cotter pin

    Check: spark plugs, fuel filter, anodes

  4. Every 200 hours (12 months)

    Replace: engine oil, oil filter, oil drain plug gasket, spark plugs, gear case oil, gear case plug gaskets, propeller cotter pin, water pump impeller

    Check: fuel filter, anodes

Source: Suzuki DF9.9/15 service manual. Specs can change by model year and serial number, so always confirm your exact model from the serial tag on the clamp bracket.

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