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Inspection intervals for idle speed 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 idle speed. 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. Check the link mechanism and the carburetor throttle valves for smooth operation.
2. Attach the tachometer cord to the spark plug high-tension cord.

Special tool required: Engine tachometer is a special tool required for this properly perform this procedure. See special tool required for more information.

3. Start and warm up the engine.

NOTE: Check and/or adjust the idle speed after the engine speed has stabilized.

4. Check the idle speed. Idle speed (in neutral gear) : 1250 – 1350 r/min.


If the idle speed is out of the specification, adjust the speed as follows:

1. Turn the pilot screw to the standard specification.

Pilot screw initial settings are in your service manual

NOTE: When turning the pilot screw fully in, lightly seat the screw only. Do not over tighten in order to avoid damaging the needle valve and the seat.

2. Turn the idle adjusting screw.

• Turning clockwise :

The engine speed becomes higher.

• Turning counterclockwise :

The engine speed becomes lower.

3. Adjust the pilot screw in small increments until a stable engine speed is achieved. Change the pilot screw setting within ±1/4 turn to the standard specification.

• Turning clockwise :

The fuel / air mixture becomes leaner.

• Turning counterclockwise :

The fuel / air mixture becomes richer.


Maintenance intervals for carburetor can be found in the maintenance chart section of your Service Manual.

Inspect the body, the float chamber, the lever, the linkage, the connector and the fuel inlet. If crack or other damage is found, replace.


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.