Clearing Clogged Blue Drain Hoses - MerCruiser 3.0 MPI Owner's Manual

Section 6 - Storage
5. Ensure that the speedometer pitot hole, gear housing water vent and drain holes, and
trim tab cavity vent and drain holes are open and unobstructed.
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 drained completely, apply sealant to the aft heat
exchanger plug.
Tube Ref No.
8. Prior to launching the boat or starting the engine, install the drain plug, 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.
Page 92
c
d
a - Gear housing vent holes
b - Trim tab cavity drain holes
a - Aft heat exchanger drain plug
Description
Perfect Seal
19
a
b
7329
c - Gear housing drain hole
d - Speedometer pitot hole
a
7184
Where Used
Aft heat exchanger plug
CAUTION
!
90-899883272 MARCH 2008
Part No.
92-34227 1