A Suzuki outboard thermostat is matched to the engine family and, in a few cases, to the year, and the opening temperature is stamped on the part. This chart was compiled by the Boat Max Online service team from Suzuki's own maintenance and owner's manuals.
Suzuki inspects the thermostat every 100 hours or 12 months and replaces it on condition: corroded, sticking, or failing a hot-water opening test. There is no fixed replacement interval in the schedule.
Suzuki outboard thermostat part numbers by model
| Models | Years | Thermostat | Opening temp |
|---|---|---|---|
| DF2.5 | 2006+ | 17670-91J02 | 48–52 °C |
| DF4A, DF5A, DF6A | 2017+ | 17670-91J02 | 48–52 °C |
| DF4, DF5, DF6 | 2002–2016 | 17670-91J02 ('02–'04), 17670-91J11 ('05–'10) 48–52; 17670-91J22 ('11–'15) 40–44 | |
| DF8A, DF9.9A | 2010+ | 17670-94J02 | 58–62 °C |
| DF9.9B, DF15A, DF20A | 2013+ | 17670-91J02 | 48–52 °C |
| DF25A, DF30A | 2015+ | 17670-94J02 | 58–62 °C |
| DF40A, DF50A, DF60A, DF50AV, DF60AV | 2010+ | 17670-93955 | 58–62 °C |
| DF70A, DF75A, DF80A, DF90A, DF100B | 2009+ | 17670-90J01 | 58–62 °C |
| DF100A, DF115A, DF140A | 2013+ | 17670-90J21 | 48–52 °C |
| DF100C, DF115B, DF140B, DF115BG, DF140BG | BG 2021+, B 2022+ | 17670-90J01 | 58–62 °C |
| DF150A, DF175A, DF200A, DF150AP, DF175AP, DF200AP | A 2019+ (DF200A 2015+), AP 2015+ | 17670-90J21 | 48–52 °C |
| DF150, DF175, DF150TG, DF175TG | 2006–2018 | 17670-90J21 (58–62 on DF150/175; 48–52 on TG) | |
| DF200, DF225, DF250 | 2004+ | 17670-90J01 | 58–62 °C |
| DF250AP, DF300AP, DF250S, DF300 | DF300 2007–2011; DF300AP 2012+; DF250AP 2013+ | 17670-90J21 (48–52) on AP; DF300 uses 17670-90J01 (58–62) | |
| DF300B, DF325A, DF350A, DF300BMD, DF350AMD | 2018+ | 17670-98L20 (58–62); DF350A 2018 only: 17670-98L00 (53–57) | 58–62 °C |
Testing a thermostat
Suspend the thermostat in a pan of water with a thermometer and heat it slowly. It should begin to open within the range in the table and be fully open a few degrees above it. One that opens early runs the engine cold (more fuel, oil dilution, carbon); one that stays shut overheats the engine within minutes. Fit a new cover gasket whenever the cover comes off.
Where to buy
Every thermostat in the table is on our Suzuki thermostat page, sold individually or with the covers and gaskets. If your motor is overheating, start with the overheating checklist before assuming the thermostat.
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, Service Data p.6. Figures are Suzuki's published values; always confirm against the owner's manual for your model and year.