Honda Outboards BF40A/BF50A Service Manual, Page 313Get this manual

BF40A-BF50A 7) Pinch the SE tubes using commercially available tube clips keeping away from tube protector as shown8) Check the intake manifold vacuum difference between cylindersTake maximum vacuum difference between each cylinderIt should be 20 mmHg (0.75 inHg) or less9) If the vacuum difference between the cylinders is not 20 mmHg (0.75 inHg) or less, adjust as follows[1] SE TUBE

[3] TUBE CLIP (2) (Commercially available)

Adjustment:

• ATV
• Jet Ski
• Outboard Motors
• Personal Watercraft
• Snowmobiles
• Stern Drives