Page 121 - REPOWER REFERENCE GUIDE (2020)

Cooling System
Collecting Water Pressure Data

IMPORTANT: For models without emissions control that are equipped with a water pressure transducer, collect the water
pressure data using a computer diagnostic system (CDS). For models with emissions control collect the water pressure data
using CDS G3 software.
Computer Diagnostic System (CDS) Purchase from Bosch Automotive Service Solutions

IMPORTANT: On seawater‑cooled Alpha sterndrive models, collect the water pressure data between the transom and the
seawater inlet on the power‑assisted steering fluid cooler. On Alpha and Bravo sterndrive models equipped with closed cooling,
collect the water pressure data within 152 mm (6 in.) of the seawater pump outlet (pressure side).
Water Inlet Hose
Select a water inlet hose according to the following requirements:
• Use a reinforced hose capable of supporting 10 in. Hg vacuum must be used to prevent the water inlet hose from
collapsing from pump suction.
• Use a hose that is oil and seawater resistant.
• Use the shortest hose length possible with the least number of bends to minimize restriction.
• Secure all connections with hose clamps.
• Fasten the hose securely, as to maintain proper routing and to prevent chafing or contact with other moving parts.
Water Pickup
You can use either a through‑the‑transom or through‑the‑hull water pickup. Select a location for the pickup that will minimize
water inlet hose length while ensuring a solid, air‑free flow of water under all operating conditions. Avoid areas with a disturbed
water flow, such as areas behind steps in the boat bottom. Also avoid locations that are too far forward or outboard because
they are prone to aeration problems at high boat trim angles and in turns.
IMPORTANT: Do not install the water pickup directly in line with the propeller, as pickup may create turbulence and allow air to
flow into the propeller slip‑stream. This will cause propeller ventilation and will adversely affect boat performance.
Openings in the water pickup should be approximately 3 mm (1/8 in.) to prevent larger debris from entering and clogging the
cooling system. We recommend a seawater strainer if the water pickup openings exceed 3 mm (1/8 in.). You should also take
appropriate measures to minimize galvanic corrosion. Some industry standards and regulations require the pickup to be
connected into the boat's bonding system to minimize stray current corrosion.
IMPORTANT: The external seawater pickup must have an integral seacock.

7532

Typical seacock

90-8M0149179 eng NOVEMBER 2018 © 2019 Mercury Marine Page 4E-9