The low-pressure fuel filter is the first filter on the motor itself: fuel from the tank passes through it upstream of the low-pressure fuel pump. Every Suzuki owner's manual in this range gives it the same replacement interval, every 400 hours or every 2 years, with an inspection at the initial 20 hours (1 month) and every 100 hours (12 months) on the schedules that spell the columns out. What differs is who does the work. On the DF9.9B through DF60A the manual says the fuel filter must be inspected by an authorized Suzuki Marine Dealer and prints no owner procedure. From the DF75/DF90A up, the filter is a cup with a water sensor under the cowling, the manual prints an inspect-and-clean procedure for the owner, and only the 400-hour replacement is assigned to the dealer. The table below says, family by family, which you have.
Which filter this is
A Suzuki four-stroke can have up to four fuel filters. The low pressure fuel filter is on the motor; on the DF75/DF90A and larger it is a filter cup with a water sensor lead wire, and the manuals describe the engine as equipped with an integral fuel filter/water separator and associated alert system, the water-in-fuel warning. The water-separating fuel filter is a boat-side filter you add between tank and motor. The low pressure fuel pump filter and high pressure fuel filter are dealer items on specific families. All three are covered at the end.
Chart legend: I means inspect and clean, adjust, lubricate, or replace if necessary; R means replace; an asterisk marks an item Suzuki recommends be done by an authorized Suzuki marine dealer or a qualified service mechanic. Intervals are judged by hours or months, whichever comes first.
Intervals and who does the work, by family
| Family (owner's manual) | Inspect | Replace | Who the manual assigns it to | Owner procedure printed? |
|---|---|---|---|---|
| DF9.9B/DF15A/DF20A (2020) | Initial 20 h (1 month); every 100 h (12 months) | Every 400 h (2 years) | "The fuel filter must be inspected by authorized Suzuki Marine Dealer periodically." Asterisked chart row. | No. Location not described. |
| DF25A/DF30A (2019) | Initial 20 h (1 month); every 100 h (12 months) | Every 400 h (2 years) | Same dealer wording; asterisked row. Low pressure fuel pump filter every 1000 h, dealer. | No. Location not described. |
| DF40A/DF50A/DF60A (2022–2024) | Initial 20 h (1 month); every 100 h (12 months) | Every 400 h (2 years) | Same dealer wording; asterisked row. | No. Location not described. |
| DF75/DF90A (2023) | Row marked I I, not asterisked | Every 400 h (2 years) | "The low pressure fuel filter must be replaced by an authorized Suzuki Marine Dealer periodically." Inspect and clean is written for the owner. | Yes: 15 steps; under the motor cover, cap held by a nut. |
| DF100A/DF115A/DF140A (2016) | I at 20, 100, 200 and 300 h, not asterisked | Every 400 h or 2 years | Dealer replaces; owner inspects and cleans. | Yes: 14 steps; bracket held by a bolt and nut. |
| DF115B/DF140B (2023) | Row marked I I, not asterisked | Every 400 h (2 years) | Dealer replaces; owner inspects and cleans. | Yes; behind the fuel hose guard. Our copy of this manual's text ends at step 6; follow the printed manual for the rest. |
| DF115BG/DF140BG (2022–2023) | I at initial 20 h and every 100 h, not asterisked | Every 400 h or 2 years | Dealer replaces; owner inspects and cleans. | Yes: 14 steps; behind the fuel hose guard, bracket bolt and nut. |
| DF150A/DF175A/DF200A (2020 and 2023) | I at initial 20 h and every 100 h, not asterisked | Every 400 h or 2 years | Dealer replaces; owner inspects and cleans. High pressure fuel filter every 1000 h, asterisked. | Yes: 15 steps; under the resonator. |
| DF225/DF250 (2021) | Row marked I I, not asterisked | Every 400 h or 2 years | Dealer replaces. Low pressure fuel pump filter and high pressure fuel filter every 1000 h, asterisked. | Yes: 14 steps; cap held by bolts. |
| DF250AP/DF300AP (2021) | Row marked I I, not asterisked | Every 400 h or 2 years | Dealer replaces. Low pressure fuel pump filter every 1000 h, asterisked. | Yes: 14 steps; cap held by bolts. |
| DF300B/DF350A (2023) | I at initial 20 h and every 100 h, not asterisked | Every 400 h or 2 years | Dealer replaces. Low pressure fuel pump filter every 1000 h, asterisked. | Yes: 15 steps; under the motor cover, cap held by bolts. |
On the DF9.9B to DF60A the filter is a dealer inspection item and the owner's manual does not say where it is; we are not going to invent a procedure the manual does not print, so have the dealer inspect it at the 20-hour and 100-hour services. On the DF75/DF90A and up, Suzuki draws a line between cleaning, which the manual writes for you, and replacing, which it assigns to the dealer. If the motor is under warranty, check with your dealer before going past the cleaning procedure. Under severe conditions you may need to perform maintenance more often than indicated in the chart.
The owner inspect-and-clean procedure (DF75/DF90A and up)
Before you start
Always take the following precautions when servicing the fuel filter: stop the motor before cleaning the fuel filter; be careful not to spill fuel, and if you do, wipe it up immediately; do not smoke, and keep away from open flames and sparks. Cleaning solvent is toxic and an irritant and can cause injury to people and pets; keep it away from children and pets.
And the notice that matters most for this part: improperly loosening the filter cup can cause sensor lead wire damage. Be careful not to twist the sensor lead wire when removing the filter cup, and disconnect the lead wire connector before removing the filter cup.
Getting to the filter
The steps are the same on every family that prints them; only the access differs.
| Family | To reach the filter | To refit it |
|---|---|---|
| DF75/DF90A | Remove the motor cover, then the nut securing the fuel filter cap. | Reinstall the fuel filter with the attaching nut. |
| DF100A/DF115A/DF140A | Remove the bolt and nut securing the bracket of the fuel filter. | Reinstall the fuel filter with bracket by securing the bolt and nut. |
| DF115B/DF140B and DF115BG/DF140BG | Remove the fuel hose guard. | DF115BG/DF140BG: reinstall the fuel filter with bracket by securing the bolt and nut. DF115B/DF140B: see the printed manual. |
| DF150A/DF175A/DF200A | Remove the bolts securing the resonator, then the resonator. | Reinstall the resonator by securing the bolts. |
| DF225/DF250 and DF250AP/DF300AP | Remove the bolts securing the fuel filter cap. | Reinstall the fuel filter with the attaching bolts. |
| DF300B/DF350A | Remove the motor cover, then the bolts securing the fuel filter cap. | Reinstall the fuel filter with the attaching bolts. |
The steps
- Turn the engine off and allow it to cool.
- Make sure the ignition key is in the OFF position. On a motor with the keyless start system, make sure the keyless start system is in the OFF state.
- Remove whatever your family's row above says: motor cover, cap nut, bracket bolt and nut, fuel hose guard, resonator or cap bolts.
- Push the connector lock tab, then disconnect the water sensor lead wire connector.
- Place a rag under the filter before removal to catch any spilled fuel.
- Separate the filter cup from the cap by turning the filter cup counterclockwise.
- Drain the fuel and water in the filter cup into a suitable container.
- Pull out the filter element. Inspect the filter element, O-ring and seal ring for damage. If they are damaged, replace them.
- Wash the filter element with clean solvent and dry it.
- Reinstall the seal ring and filter element in their original positions.
- Verify that the O-ring is in place in the top of the filter cup and screw the filter cup back into place.
- Connect the water sensor lead wire connector.
- Refit the filter: attaching nut, bracket bolt and nut, resonator bolts or cap bolts, as the row above says.
- Restart the engine and check that there are no leaks around the fuel filter.
Tightening and priming
No torque value is printed for the filter cup or any of its fasteners in these owner's manuals: screw the cup back into place, secure the fasteners and prove the job with the leak check. There is no separate bleeding or priming step either; the procedure goes straight from reassembly to restarting the engine. If fuel weeps at the cup afterward, stop and recheck that the O-ring is seated in the top of the cup and the seal ring and element are in their original positions.
What you find in the cup
Water. Every manual with the procedure adds the same note: if any water exists in the fuel filter cup, remove the cup and drain the water, and always dispose of excess fuel safely. Water in the cup is also what trips the water-in-fuel alert, which activates if water separated from the fuel exceeds a specific volume. If it came on, stop the engine immediately if wind and water conditions are safe to do so, and check the fuel filter/water separator for water, or consult your authorized Suzuki marine dealer; the DF150A/DF175A/DF200A manual sends you from that alert straight to the procedure above. If you keep finding water, the fix is upstream: a boat-side water-separating filter and better fuel. Suzuki's rules are in the fuel requirements guide; in short, gasoline-ethanol blends may be used if the ethanol content is not greater than 10%, and alcohol-free gasoline is recommended whenever possible.
Varnish and gum. Gasoline kept in the fuel tank for long periods of time will produce varnish and gum, which can damage the engine. A brown, sticky element or a tide line in the cup is that fuel; clean the element, then deal with what is in the tank.
Damaged O-ring or seal ring. If the element, O-ring or seal ring is damaged, replace it. A nicked O-ring is the usual cause of a weeping cup after reassembly.
A clogged element. The DF75/DF90A troubleshooting table lists a clogged fuel filter under hard starting, unstable idle or stalling, and engine speed that will not increase. The small-motor manuals do not list it; their tables point at the fuel hose, tank vent and spark plug first.
The other fuel filters on a Suzuki
Water-separating fuel filter (boat side). Suzuki recommends installing one between the boat's fuel tank(s) and outboard motor(s) in the owner's manuals from the DF9.9B up, to help prevent water in the boat's tank from contaminating the motor. Replace the filter element every 12 months, or more frequently if recommended by the filter manufacturer. It lives on the boat, so this one is yours to change: the store carries the assembly and element for 140 hp and below and 150 hp and above.
Low pressure fuel pump filter. The DF25A/DF30A manual lists it separately: inspected by an authorized Suzuki Marine Dealer periodically, replaced with a new one every 1000 hours. The DF225/DF250, DF250AP/DF300AP and DF300B/DF350A charts carry the same 1000-hour line as an asterisked item. We did not find it in the other charts; check yours.
High pressure fuel filter. The DF150A/DF175A/DF200A (2020 and 2023) and DF225/DF250 charts list it as an asterisked item: replace every 1000 hours, dealer work. The store lists the internal engine fuel filter for the DF115A through DF200A for shops and owners who do that job; confirm fitment from your model code and serial number.
Fuel line. The "Breather & Fuel line" chart row is an inspect item at the initial 20 hours and every 100 hours. If the hose from the filter is hard, cracked or weeping at the fittings, replace it when you do the filter.
Parts for this job
The low-pressure filter itself is the Suzuki complete fuel filter; the full range of motor-side filters, elements and seals is in Suzuki fuel filters and fuel filters and separators. The filter connection fuel hose and the rest of the hoses are in fuel hoses and lines. Have the model code and serial number from the ID plate ready; the store will confirm fitment from the model and serial number if you are not sure. Boat Max Online is an authorized Suzuki, Honda and Yamaha dealer; orders over $149 ship free to the lower 48.
Sources: Suzuki owner's manuals for DF9.9B/15A/20A (99011-89LA0-03B), DF25A/30A (99011-94L60-03B), DF40A/50A/60A (99011-88LB0-03B), DF75/90A (99011-87LC0-03B), DF100A/115A/140A (99011-90J70-03B), DF115B/140B (99011-99L30-03B), DF115BG/140BG (99011-99L20-03B), DF150A/175A/200A (99011-96LC0-03B and 99011-96LM0-03B), DF225/250 (99011-93JL0-03B), DF250AP/300AP (99011-98JB0-03B) and DF300B/350A (99011-98L60-03B). Figures are Suzuki's published values; confirm against the manual for your model year and serial number.