Valve clearance (Suzuki's manuals call it tappet clearance or valve lash) is the small gap between each valve and the rocker arm or cam follower that opens it, measured with the engine cold. Suzuki's 2025 four-stroke maintenance manual prints the figure for every family from the DF2.5 to the DF350A under one heading, "Tappet clearance (Valve lash) (Cold engine condition) (mm)", and the first chart below reproduces that table: intake and exhaust clearance in millimeters, by model and model year. The second chart adds what the service manuals and owner's manuals say for the families we hold manuals for: adjustment type, inspection interval, lock nut torque and head cover bolt torque.
Every figure is for a cold engine. And in the Suzuki owner's manuals we have for the DF2.5, DF4A/6A, DF9.9B/15A/20A, DF40A/50A/60A and DF100A/115A/140A, valve lash is an asterisked item in the maintenance chart. The DF2.5 and DF4A/6A manuals spell out what the asterisk means: "Suzuki recommends that only your authorized Suzuki marine dealer or a qualified service mechanic perform maintenance on those items in the chart above which are marked with an asterisk." The portables we hold service manuals for (DF2.5, DF4/5/6, DF9.9B/15A/20A and DF25A/30A) use a screw-and-lock-nut adjuster, so the service manual procedure needs a feeler gauge and hand tools. The DF40A/50A/60A, DF70A through DF100B and DF100A/115A/140A use shims, which means the shim thickness has to be measured and a replacement calculated: dealer work. If the motor is under warranty, check with your dealer before opening the cylinder head cover.
Suzuki valve clearance chart, DF2.5 to DF350A (2025 maintenance manual)
Figures are in millimeters as printed; the 2025 manual prints no inch equivalents in this table. "2006 on" means the 2006 model year and later. Where the manual's layout made a row hard to read in the copy we have, the row says so: confirm against the service manual for your serial number.
| Model | Model years | Intake (mm) | Exhaust (mm) | Note |
|---|---|---|---|---|
| DF2.5 | 2006 on | 0.13 – 0.17 | 0.13 – 0.17 | Matches the DF2.5 service manual |
| DF4 / DF5 / DF6 (earlier models, not the A series) | 2002 – 2015 | 0.03 – 0.07 | 0.03 – 0.07 | Printed once beside the 2005 – 2010 range and read as covering all three year ranges; the DF4/5/6 service manual gives the same figure |
| DF4A / DF5A / DF6A | 2017 on | 0.13 – 0.17 | 0.13 – 0.17 | |
| DF8A / DF9.9A | 2006 on | 0.16 – 0.20 | 0.16 – 0.20 | |
| DF9.9 / DF15 | 2000 – 2004 | 0.08 – 0.12 | 0.13 – 0.17 | Row flagged in our extraction (the pressure columns interleave); confirm in your manual |
| DF9.9 / DF15 | 2005 – 2012 | 0.18 – 0.22 | 0.18 – 0.22 | Row flagged in our extraction; confirm in your manual |
| DF9.9B / DF15A / DF20A | 2013 on | 0.18 – 0.22 | 0.18 – 0.22 | Matches the DF9.9B/15A/20A service manual |
| DF25 (V2) | 2006 – 2014 | 0.03 – 0.07 | 0.03 – 0.07 | |
| DF25 / DF30 | 2006 – 2010 | 0.13 – 0.17 | 0.13 – 0.17 | |
| DF25A / DF30A | 2015 on | 0.18 – 0.22 | 0.20 – 0.24 | Matches the DF25A/30A service manual |
| DF40 / DF50 | 2000 – 2010 | 0.18 – 0.22 | 0.18 – 0.22 | |
| DF40A / DF50A / DF60A / DF50AV / DF60AV | 2010 on | 0.18 – 0.22 | 0.28 – 0.32 | Matches the DF60A service manual |
| DF60 / DF70 | 2000 – 2009 | 0.11 – 0.15 | 0.13 – 0.17 | |
| DF70A / DF80A / DF90A / DF100B | 2009 on | 0.23 – 0.27 | 0.30 – 0.34 | Matches the DF70A – DF100B service manual (which also covers the DF75) |
| DF90 / DF100 / DF115 | 2001 – 2012 | 0.23 – 0.27 | 0.23 – 0.27 | Shares one printed row with the DF140 |
| DF140 | 2002 – 2012 | 0.23 – 0.27 | 0.23 – 0.27 | |
| DF100A / DF115A / DF140A | 2013 on | 0.23 – 0.27 | 0.23 – 0.27 | Matches the DF100A/115A/140A service manual |
| DF100C / DF115B / DF140B | 2022 on | 0.23 – 0.27 | 0.33 – 0.37 | Shares one printed row with the DF115BG/140BG |
| DF115BG / DF140BG | 2021 on | 0.23 – 0.27 | 0.33 – 0.37 | |
| DF150 / DF175 | 2006 on | 0.23 – 0.27 | 0.30 – 0.34 | |
| DF150TG / DF175TG | 2014 – 2016 | 0.23 – 0.27 | 0.30 – 0.34 | |
| DF150A / DF175A | 2019 on | 0.23 – 0.27 | 0.30 – 0.34 | Printed as one group with the DF150AP/175AP |
| DF150AP / DF175AP | 2017 on | 0.23 – 0.27 | 0.30 – 0.34 | |
| DF200A / DF200AP | 2015 on | see your manual | see your manual | The model name prints between the DF150A/175A group and the DF200/225/250 row in our copy, so we do not assign it figures here |
| DF200 / DF225 / DF250 | 2004 on | 0.23 – 0.27 | 0.33 – 0.37 | |
| DF300 | 2007 – 2011 | 0.23 – 0.27 | 0.33 – 0.37 | |
| DF250AP / DF300AP | 2012 on | 0.23 – 0.27 | 0.33 – 0.37 | |
| DF300B / DF325A | 2020 on | 0.23 – 0.27 | 0.33 – 0.37 | |
| DF350A | 2018 on | 0.23 – 0.27 | 0.33 – 0.37 | The DF350A lines print no lash of their own; the figures on the DF300B/325A line above are read as a shared cell. Confirm in your manual |
Adjustment type, interval and torques by family (service and owner's manuals)
This table covers only the families we hold a Suzuki service manual for. Inch figures are the service manual's own conversions. The DF8A/9.9A, the older DF25/30 and DF40/50, the DF115B/140B/BG and every family from the DF150 up appear only in the chart above: their adjustment method and interval are not stated in the manuals we have.
| Family (service manual) | Clearance, cold, IN / EX | Adjustment type | Inspection interval | Lock nut torque | Cylinder head cover bolt torque |
|---|---|---|---|---|---|
| DF2.5 (99500-97J01-01E) | IN and EX 0.13 – 0.17 mm (0.005 – 0.007 in) | Adjusting screw and lock nut on the rocker arm | Initially after 20 hours (1 month) and every 200 hours (12 months). Dealer item (asterisk) in the 2019 owner's manual | 7 N·m (0.7 kg-m, 5.0 lb-ft) | 7 N·m (0.7 kg-m, 5.0 lb-ft), four bolts, diagonally |
| DF4 / DF5 / DF6, earlier models (99500-91J03-01E) | IN 0.03 – 0.07 mm (0.001 – 0.003 in); EX 0.03 – 0.07 mm (0.001 – 0.003 in) | Pivot nut and lock nut on the rocker arm | Initially after 20 hours (1 month) and every 200 hours (12 months) | 11 N·m (1.1 kg-m, 8.0 lb-ft) | 8 N·m (0.8 kg-m, 6.0 lb-ft) |
| DF4A / DF5A / DF6A (no service manual in our library) | IN and EX 0.13 – 0.17 mm (2025 maintenance manual) | Not stated in the manuals we have | Dealer item (asterisk) with two inspection marks in the 2020 – 2024 owner's manual; which columns they fall in does not read cleanly in our copy | Not stated | Not stated |
| DF9.9B / DF15A / DF20A (99500-89L00-01E) | IN 0.18 – 0.22 mm (0.007 – 0.009 in); EX 0.18 – 0.22 mm (0.007 – 0.009 in) | Adjusting screw and lock nut (the manual lists a "valve adjusting lock nut") | Initially after 20 hours (1 month) and every 200 hours (12 months). Dealer item (asterisk) in the 2020 owner's manual | 11 N·m (1.1 kgf-m, 8.0 lbf-ft) | 10 N·m (1.0 kgf-m, 7.2 lbf-ft) |
| DF25A / DF30A (99500-94L10-01E) | IN 0.18 – 0.22 mm (0.007 – 0.009 in); EX 0.20 – 0.24 mm (0.008 – 0.009 in) | Adjusting screw and lock nut (the manual lists a "valve adjusting screw lock nut") | Initially after 20 hours (1 month) and every 200 hours (12 months) | 11 N·m (1.1 kgf-m, 8.0 lbf-ft) | 10 N·m (1.0 kgf-m, 7.2 lbf-ft) |
| DF40A / DF50A / DF60A (DF60 manual 99500-88L01-01E) | IN 0.18 – 0.22 mm (0.007 – 0.009 in); EX 0.28 – 0.32 mm (0.011 – 0.013 in) | Shim: IN A = B + (C – 0.20 mm), EX A = B + (C – 0.30 mm) | Service manual (2010 base): every 200 hours (12 months). The 2022 owner's manual lists valve lash as a dealer item (asterisk) with one inspection mark | None (shim type) | 11 N·m (1.1 kgf-m, 8.0 lbf-ft) |
| DF70A / DF75 / DF80A / DF90A / DF100B (99500-87L10-01E) | IN 0.23 – 0.27 mm (0.009 – 0.011 in); EX 0.30 – 0.34 mm (0.012 – 0.013 in) | Shim under the cam follower (formula not in our extract) | Every 300 hours (36 months) per the service manual. The 2023 DF75/DF90A owner's manual prints the same clearances in its specification table; its schedule rows do not read cleanly in our copy | None (shim type) | 11 N·m (1.1 kgf-m, 8.0 lbf-ft) |
| DF100A / DF115A / DF140A (99500-92J00-01E) | IN 0.23 – 0.27 mm (0.009 – 0.011 in); EX 0.23 – 0.27 mm (0.009 – 0.011 in) | Shim: IN and EX A = B + (C – 0.25 mm) | Every 300 hours (36 months) in both the service manual and the 2016 owner's manual, where it is a dealer item (asterisk) | None (shim type) | 11 N·m (1.1 kgf-m, 8.0 lbf-ft) |
The intervals line up with Suzuki's wider schedule: the portables get a 20-hour first check and then a 200-hour cycle, the DF70A through DF140A go 300 hours. The maintenance schedule explainer walks through what else falls at those marks, and the torque spec chart has the rest of the fasteners you will touch on the way in.
Screw-and-lock-nut vs shim: what each means for you
Screw type (DF2.5, DF4/5/6, DF9.9B/15A/20A, DF25A/30A)
A threaded adjuster sits in the rocker arm with a lock nut behind it. You hold the adjuster, loosen the nut, turn the adjuster until a feeler gauge of the right thickness drags lightly between the valve stem and the rocker, then tighten the lock nut to the torque in the table while still holding the adjuster, and recheck. No parts are consumed except the head cover gasket. It is a tools-and-patience job, but Suzuki still asterisks it in the owner's manuals we can read, so it is on the dealer-recommended list.
Shim type (DF40A/50A/60A, DF70A to DF100B, DF100A/115A/140A)
There is no adjuster. The clearance is set by a hardened shim of a specific thickness between the cam and its follower, so correcting it means measuring the existing clearance, calculating the shim you need from the manual's formula, and swapping it. The DF60A manual states the formula as "IN. side: A = B + (C – 0.20 mm) EX. side: A = B + (C – 0.30 mm) A: Correct thickness of shim for proper tappet clearance (mm) B: Thickness of original shim (mm) C: Original tappet clearance (mm)", and it adds: "When installing shim, identification mark on the shim should face down (towards tappet)." The DF100A/115A/140A manual uses A = B + (C – 0.25 mm) for both sides. Measuring is possible with the cover off, but swapping shims is dealer work.
The screw-type procedure, as the service manuals print it
This is an overview of the DF2.5 and DF4/5/6 procedure, quoted where the step matters. It is not a substitute for the service manual, which has the drawings that identify the parts.
- Engine cold. Remove the motor cover, recoil starter and spark plug, then the four bolts and the cylinder head cover.
- Bring the piston to top dead center on the compression stroke. Both manuals print it the same way: "Rotate the flywheel clockwise to bring the piston to the Top Dead Center (TDC) on a compression stroke." Only ever turn it clockwise. The same manuals say "Rotate the crankshaft clockwise to prevent water pump impeller damage."
- Confirm you are on the compression stroke, not exhaust, with the rocker test: "If both rocker arms do not move at all, the piston is at the position on a compression stroke. If any rocker arm moves, the piston is at the TDC position on an exhaust stroke. Rotate the flywheel one more turn."
- Measure the clearance between the valve stem end and the rocker arm with a feeler gauge and compare it with the chart.
- Adjust if it is out. DF4/5/6: "Loosen the valve adjusting lock nut 1 while holding the pivot nut 2. Turn the pivot nut 2 to bring the valve clearance to within the specification." DF2.5: "Tighten the lock nut 1 to the specified torque while holding the adjusting screw 2." Recheck after tightening, because the nut moves the setting.
- Refit the head cover with a new gasket (Suzuki's general rule: gaskets, locking nuts and similar parts removed in service are always replaced with new) and "Tighten the four cylinder head cover bolts diagonally to the specified torque."
The DF9.9B/15A/20A and DF25A/30A are the same screw-and-lock-nut design with an 11 N·m lock nut and 10 N·m cover bolts, but they drive the cam with a timing belt (inspected every 200 hours, replaced every 4 years), so use that family's service manual for finding TDC rather than the single-cylinder rocker test above. One warning from the DF9.9B/15A/20A manual applies if you go further than the cover: "Do not rotate the cam pulley and/or crankshaft with timing belt removed."
Symptoms of valves out of adjustment
Keep this short because the only real test is a feeler gauge. Clearance that has closed up (too tight) holds the valve slightly off its seat, so compression bleeds off: hard starting, rough idle, and in the long run a burned exhaust valve. The low-compression cause list in every Suzuki service manual we hold includes "Poor seating of valves", which is why a compression test is the right first step when a motor that once ran well starts hard. Clearance that has opened up (too loose) is noisier, a light ticking from the top of the powerhead at idle, and costs a little lift and power. Neither is an emergency, but neither fixes itself, and a tight valve gets worse with hours.
Parts for this job
On the screw-type portables the only consumable is the head cover gasket, in our Suzuki OEM gaskets, seals and O-rings collection. Shims, rocker arms, adjusters and lock nuts for the whole range are in Suzuki OEM valve train and camshafts, and Suzuki's special tools are in Suzuki OEM service tools. If you are doing the 20-hour or 200-hour service at the same time, the model guides cover the rest: DF2.5, DF4A/5A/6A, DF9.9B/15A/20A and DF25A/30A. Orders over $149 ship free to the lower 48.
Sources: Suzuki 4-Stroke Outboard Maintenance Manual (2025.02 edition); Suzuki owner's manuals for DF2.5, DF4A/6A, DF9.9B/15A/20A, DF25A/30A, DF40A/50A/60A, DF75/90A and DF100A/115A/140A; Suzuki service manuals 99500-97J01-01E (DF2.5), 99500-91J03-01E (DF4/5/6), 99500-89L00-01E (DF9.9B/15A/20A), 99500-94L10-01E (DF25A/30A), 99500-88L01-01E (DF60), 99500-87L10-01E (DF70A/80A/90A/100B) and 99500-92J00-01E (DF100A/115A/140A). Figures are Suzuki's published values; confirm against the manual for your model year and serial number.