Clearing Clogged Blue Drain Hoses - Mercury 3.0 MPI ECT Operation & Maintenance Manual

5. Ensure the gear housing water vent and drain holes, speedometer pitot hole, and trim tab cavity vent and drain holes are
open and unobstructed.
c
d
6. Crank the engine over slightly with the starter motor to purge any water trapped in seawater pickup pump. Do not allow the
engine to start.
7. After the cooling system has been drained completely, apply sealant to the aft heat exchanger plug.
Tube Ref No.
Perfect Seal
19
8. Prior to launching the boat or starting the engine, install the drain plugs, reconnect the hoses, and tighten all hose clamps
securely.
9. If the boat was drained in the water, open the seacock (if equipped) or unplug and reconnect the water inlet hose prior to
operating the engine.

Clearing Clogged Blue Drain Hoses

Disconnecting the blue drain hoses can cause serious burns due to hot water. Check all hose connections before operating
the engine and never disconnect the hoses until the engine has had suffient time to cool.
1. If the engine can be started proceed to Step 2. If the engine cannot be started, proceed to Step 8.
2. If one hose is flowing freely, reconnect it to the bracket.
3. Ensure the clogged blue drain hose is in the correct position below its connection point on the block.
90-8M0113856 DECEMBER 2015
eng
a
b
7329
a - Heat exchanger drain plug
a
7184
Description
a - Gear housing vent holes
b - Trim tab cavity drain holes
c - Gear housing drain hole
d - Speedometer pitot hole
Where Used
Aft heat exchanger plug
CAUTION
!
Section 5 - Storage
Part No.
92-34227Q02
Page 83