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Suzuki DF90 / DF100 / DF115 service guide

Oil, gear oil, spark plugs and the service schedule for the Suzuki DF90 / DF100 / DF115 (90 to 115 hp, four-stroke), from the factory service manual, plus how we service it in Hawaiʻi.

Models covered: Suzuki DF90 (prefix 09001F) and DF115 / DF115W (prefix 11501F) four-strokes, 4 cylinder 1950 cc DOHC, multi-point fuel injection, 2000 to 2008, and the 2009 DF100. The DF140 has its own sheet.

Quick answers

How much oil does a Suzuki DF90 / DF100 / DF115 take?
5.5 L (5.8/4.8 US/Imp. qt) oil change only; 5.7 L (6.0/5.0 US/Imp. qt) with filter change.
What engine oil does a Suzuki DF90 / DF100 / DF115 use?
API SE, SF, SG, SH or SJ, SAE 10W-40; the 2009 DF100 adds NMMA FC-W 10W-40.
What gear oil does a Suzuki DF90 / DF100 / DF115 use, and how much?
Suzuki Outboard Motor Gear Oil (SAE #90 hypoid gear oil). Quantity: 1050 ml (35.5/37.0 US/Imp. oz); fill through the drain hole until it flows from the level hole.
What spark plug does a Suzuki DF90 / DF100 / DF115 use?
NGK BKR6E, resistor type only, qty 4. Gap: 0.7 to 0.8 mm (0.028 to 0.031 in).
How often should a Suzuki DF90 / DF100 / DF115 be serviced?
The factory schedule lists: Initial 20 hours or 1 month; Every 50 hours or 3 months; Every 100 hours or 6 months; Every 200 hours or 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 DF90 / DF100 / DF115?
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 DF90 / DF100 / DF115?
625 ± 25 r/min, in gear about 625; procedure: 600 to 650 r/min in neutral, set 625 ± 25 with the by-pass air screw in fixed mode.
What is the propeller nut torque on a Suzuki DF90 / DF100 / DF115?
55 N·m (5.5 kg-m, 40.0 lb-ft); new cotter pin.

Maintenance specs

Engine oilAPI SE, SF, SG, SH or SJ, SAE 10W-40; the 2009 DF100 adds NMMA FC-W 10W-40
Engine oil quantity5.5 L (5.8/4.8 US/Imp. qt) oil change only; 5.7 L (6.0/5.0 US/Imp. qt) with filter change
Engine oil filterOil the O-ring, hand tight until it touches, then 3/4 turn: 14 N·m (1.4 kg-m, 10.0 lb-ft). From 2006 the oil filter stand is 40 N·m (4.0 kg-m, 29.0 lb-ft)
Engine oil drain plug13 N·m (1.3 kg-m, 9.5 lb-ft), new gasket
Gear oilSuzuki Outboard Motor Gear Oil (SAE #90 hypoid gear oil)
Gear oil quantity1050 ml (35.5/37.0 US/Imp. oz); fill through the drain hole until it flows from the level hole
Gear oil drain and level plugs13 N·m (1.3 kg-m, 9.5 lb-ft), new gaskets
Gearcase leak test100 kPa (1.0 kg/cm², 14.2 psi) through the oil level hole; start at 20 to 40 kPa (0.2 to 0.4 kg/cm², 2.8 to 5.7 psi). Do not exceed 110 kPa (1.1 kg/cm², 15.6 psi)
Spark plugNGK BKR6E, resistor type only, qty 4.
Spark plug gap0.7 to 0.8 mm (0.028 to 0.031 in)
Spark plug torque28 N·m (2.8 kg-m, 20.0 lb-ft)
Idle speed625 ± 25 r/min, in gear about 625; procedure: 600 to 650 r/min in neutral, set 625 ± 25 with the by-pass air screw in fixed mode
Thermostat operating temperature58 to 62 °C (136 to 144 °F)
AnodesReplace when 2/3 is gone; never paint; Suzuki Silicone Seal on the anode bolts.
Propeller nut55 N·m (5.5 kg-m, 40.0 lb-ft); new cotter pin
Power trim and tilt fluidDexron III automatic transmission fluid or equivalent; check tilted full up with the manual tilt lock lever down: full when oil shows at the filler plug. Manual release valve 3.6 N·m (0.36 kg-m, 2.6 lb-ft), do not overtighten
Tappet clearance, coldIN and EX 0.23 to 0.27 mm (0.009 to 0.011 in); shim type. Left hand rotation powerhead: turn the crankshaft counterclockwise only. Camshaft housing bolts 11 N·m (1.1 kg-m, 8.0 lb-ft)

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 or 1 month

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

  2. Every 50 hours or 3 months

    Replace: gear case plug gaskets

    Check: fuel filter, anodes

  3. Every 100 hours or 6 months

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

    Check: fuel filter, anodes

  4. Every 200 hours or 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 DF90/115 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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