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Inspection intervals for valve clearance can be found in the maintenance chart section of your Service Manual.


The following directions are examples of typical procedures required for maintenance, checking and adjusting valve clearance. Since procedures differ between year, make and model Suzuki outboard 4-Stroke engines its mandatory to acquire exact servicing information from your factory service manual for exact service guidelines.


1. Remove the following parts :

• Engine cover
• Recoil starter
• Spark plug
• Engine cover seal

2. Remove the four bolts 1 and the cylinder head cover.
3. Rotate the flywheel clockwise to bring the piston to the Top Dead Center (TDC) on a compression stroke.

CAUTION: Rotate the crankshaft clockwise to prevent water pump impeller damage.


• To confirm whether the piston is at the TDC position on a compression stroke or on a exhaust stroke, rotate the flywheel within the oorrect degre beyond the TDC position.

- 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.

• The valve clearance specification is for COLD engine condition

4. Measure the valve clearance by inserting thickness gauge between the valve stem end and the rocker arm.

Special tool required : Thickness gauge is one of the special tools required to perform proper measurements when measuring valve cleareance.

Valve clearance (cold engine condition) : See specifications for correct intake and exhaust cleareance specifications.

If the valve clearance is out of the specification, adjust the clearance.


5. Loosen the valve adjusting lock nut 1 while holding the pivot nut.
6. Turn the pivot nut to bring the valve clearance to within the specification.
7. Tighten the lock nut to the specified torque while holding the pivot nut.

Thighten Torque Valve adjusting lock nut : See torque specs for factory specifications.

8. Recheck the valve clearance.


Installation is reverse order of removal with the special attention to the following steps.

• Tighten the four cylinder head cover bolts diagonally to the specified torque.

Cylinder head cover bolt : Refer to torque specifications.

WARNING: Do not re-use the gasket once removed. Always use a new gasket.

• Make sure that the cylinder head cover gasket is installed correctly.


Suzuki Models / Horsepower / Model Years

DF4 DF4 DF6 DF9.9 DF15 DF25 DF30 DF40 DF50 DF50 DF40QH DF50QH DF40T DF50T DF40Y DF50Y DF70 DF80 DF90 DF100 DF115 DF175 QH T Y 4HP 5HP 6HP 9.9HP 15HP 25HP 30HP 40HP 50HP 60HP 70HP 90HP 115HP 140HP 150HP 175HP 4 5 6 9.9 15 25 30 40 50 60 70 90 100 115 140 150 175 HP 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 99 00 01 02 03 04 05 06 07 08 09 10 11 Service Manual Repair Owner's Guide Diy Boat Engine Four Stroke 4-Stroke How To Fix.