Every Suzuki lower unit is filled from the bottom until oil runs out of the level hole, so you rarely need to measure, but you do need to know how much to buy. This chart was compiled by the Boat Max Online service team from Suzuki's own maintenance and owner's manuals.
Suzuki's gear oil specification is Suzuki Outboard Motor Gear Oil (hypoid) or, if it is not available, SAE 90 hypoid gear oil rated API GL-5. We stock ECSTAR SAE 90 gear oil and a pump that threads onto the bottle.
Suzuki outboard gear oil capacity by model
| Models | Years | Gear oil capacity | Note |
|---|---|---|---|
| DF2.5 | 2006+ | 60 ml (2.0 fl oz) | Owner's manual says approx. 0.07 L; either way, fill until it runs from the level hole |
| DF4A, DF5A, DF6A | 2017+ | 190 ml (6.4 fl oz) | |
| DF4, DF5, DF6 | 2002–2016 | 190 ml (6.4 fl oz) | |
| DF8A, DF9.9A | 2010+ | 250 ml (8.5 fl oz) | |
| DF9.9B, DF15A, DF20A | 2013+ | 250 ml (8.5 fl oz) | |
| DF25A, DF30A | 2015+ | 330 ml (11.2 fl oz) | Drained tilted fully up with the starboard side down, then lowered upright to fill; drain plug first |
| DF40A, DF50A, DF60A, DF50AV, DF60AV | 2010+ | 610 ml (20.6 fl oz) | DF50AV/60AV: 1,050 ml |
| DF70A, DF75A, DF80A, DF90A, DF100B | 2009+ | 850 ml (28.7 fl oz) | |
| DF100A, DF115A, DF140A | 2013+ | 1,050 ml (35.5 fl oz) | |
| DF100C, DF115B, DF140B, DF115BG, DF140BG | BG 2021+, B 2022+ | 1,050 ml (35.5 fl oz) | |
| DF150A, DF175A, DF200A, DF150AP, DF175AP, DF200AP | A 2019+ (DF200A 2015+), AP 2015+ | 1,100 ml (37.2 fl oz) | Three plugs: vent, drain and a separate level plug |
| DF150, DF175, DF150TG, DF175TG | 2006–2018 | 1,100 ml (37.2 fl oz) | |
| DF200, DF225, DF250 | 2004+ | 1,100 ml (37.2 fl oz) | |
| DF250AP, DF300AP, DF250S, DF300 | DF300 2007–2011; DF300AP 2012+; DF250AP 2013+ | 1,100 ml (37.2 fl oz) | |
| DF300B, DF325A, DF350A, DF300BMD, DF350AMD | 2018+ | 3,200 ml (108.2 fl oz) | Two procedures by year, see below |
Suzuki's gear oil procedure (DF2.5 through DF140)
- Motor upright on a level surface, propeller removed if you want to check the shaft seal at the same time.
- Remove the drain plug first (the lower one), then the level (air vent) plug. Drain into a pan and read the oil: amber to dark is normal; milky means water is getting in and the seals need attention before you refill.
- Pump new oil in through the lower drain hole until oil just starts to run out of the upper level hole.
- Fit the level plug first with a new gasket, then quickly remove the pump and fit the drain plug with a new gasket.
- Wait about 10 minutes, remove the level plug and top up if the level has dropped, then refit it.
The DF25A/30A is the exception on position: the owner's manual has you tilt the motor fully up and turn the starboard side down so the drain plug is at the bottom, remove the drain plug then the level plug, and lower the motor to upright before filling.
DF150A–DF300AP: three plugs
These gearcases have an air vent plug (upper), a drain plug (lower) and a separate level plug. Drain plug first, then vent plug; fill through the drain hole until oil exits the vent hole; refit the vent plug, then the drain plug. Run the engine a few minutes, wait 10 minutes, then check at the level plug and top up there.
DF300B, DF325A and DF350A: 3.2 litres, two procedures by year
The dual-prop gearcase holds 3.2 L. On 2018–2022 motors Suzuki fills it with the motor trimmed up 4 degrees from horizontal. On 2023-and-newer motors (including the BMD/AMD) the maintenance manual drains it in full trim-up after removing the port and starboard water filters, then has the motor placed upright and filled through the drain hole until oil exits the adjustment hole; plugs 9–11 N·m, recheck after 10 minutes, water-filter bolts 1–2 N·m. Follow the manual page for your year; it is not the same job as the smaller motors.
Intervals and gaskets
Gear oil is replaced at the first 20 hours or 1 month, then every 100 hours or 12 months, and always before winter storage. Use new plug gaskets every time; the lower unit gear oil change kit has the oil, pump and gaskets together. Step-by-step photos are in our gear lube change guide.
Sources: Suzuki 4-Stroke Outboard Maintenance Manual (Feb 2025); Suzuki owner's manuals for each model family (in our service library); Suzuki 4-Stroke Outboard Maintenance Manual, Oil Data p.4. Figures are Suzuki's published values; always confirm against the owner's manual for your model and year.