Updated: 5 days ago
The bleed lines on Mercury V6 2-stroke outboards (150, 175, 200, 225, 245, 260 hp, Pro Max) are to pump fuel and oil from reed cages back into cylinders. The lines are connected 180 degrees apart to bleed off pooled oil in the reed cage area.
Bleed lines are important because fuel and oil can puddle in the bottom of the cages and create a rough idle.
When replacing bleed lines, you should:
Replace all of the lines
Cut the lines from a 10' or 20' roll
Follow the specific routing and lengths listed in the OEM Service Manual
Make sure all check valves on the bleed lines are functioning properly
Replace the lines one at a time
Pay attention to the length of the lines, especially any that cross behind the intake manifold
If you decide to remove all the bleed hoses, make sure to leave and or replace the lines that lubricant the top cap bearing and center main bearings. Those are crucial to keep your motor from seizing up.
Why keep the lines? These are helpful for idling for long periods of time such as trolling, cruising, or going from fishing hole to hole.
Why remove the lines? Racers often remove the lines as they might be running wide-opened throttle for periods of time where there is little chance of fuel pooling. Removing the lines reduces the chance of a vacuum leak which could mean out a motor.
We carry bleed lines for outboards in Tygon yellow, blue, and red translucent colors. We prefer the translucence lines and more importantly the lubricating lines to ensure you have clear and unblocked passages.