Heat Exchanger Disassembly; Cleaning And Inspection; Heat Exchanger Repair - Mercury MerCruiser Service Manual

Models with Closed Cooling
7. Remove the two straps that fasten the heat exchanger to the engine.
8. Remove the heat exchanger.

Heat Exchanger Disassembly

IMPORTANT: Do not remove the air pump and air pump bracket if they are mounted to the engine compartment.
1. Remove the air manifold.
2. Remove the fasteners attaching the end caps to the heat exchanger.
3. Remove the end caps and gaskets.
b
c
d

Cleaning and Inspection

1. Clean the old gasket material and sealant from the surfaces. Do not nick or gouge the surfaces.
2. Use a long rod and wire brush to clean out heat exchanger tubes.
3. Inspect each part for cracks or other damage. Replace as necessary.
4. Clean and paint the exterior surfaces as required to prevent corrosion.

Heat Exchanger Repair

IMPORTANT: Braze with BCUP 2 rod or silver solder. Do not melt the other joints during repair.
• Internal leaks can be repaired by brazing shut the ends of the leaking tube. This is only a temporary fix because usually
another tube will start leaking after a short period of time and this also causes a reduction in the cooling capacity. Do not
close more than three tubes.
• Fittings and drains that have been broken off the heat exchanger can be reattached by brazing.
b
c
d
After repairs are complete:
1. Assemble the heat exchanger. Tighten the heat exchanger end cap fasteners to the specified torque.
Description
Heat exchanger end cap fasteners
2. Fasten the air manifold and bracket to the heat exchanger. Tighten the nut to the specified torque.
Page 6C-18
a - Heat exchanger
a
b - Gasket
c - End cap
d - O‑rings
6747
a - Heat exchanger
a
b - Gasket
c - End cap
d - O‑rings
6747
© 2016 Mercury Marine
Nm lb‑in.
14.9 131.8
90-8M0099748 eng DECEMBER 2015
lb‑ft
–