Page 283 - REPOWER REFERENCE GUIDE (2020)

Critical Procedures

• Do not set the engine down on the drive shift cable during installation, as this will crush the inner cable tubing and cause
difficult shift operation.
Proper Exhaust Pipe to Transom Clearance

The exhaust Y‑pipe (bullhorn) requires clearance between the pipe and the transom. Interference is an indication that the
transom cutout was not made correctly. Failure to correct this could result in a water leak from the exhaust pipe not sealing
properly on the transom assembly. A quick check when installing the exhaust pipe will avoid the need to remove the engine
later to fix the leak.

Typical application
a - Exhaust Y‑pipe
b - Boat transom
a c - Clearance is required on both sides
b

c 12695

Oil System Priming for Remanufactured Engines and Longblocks

All MerCruiser remanufactured 4‑cycle engines and longblocks are temporarily fit with electrical, cooling, and fuel systems to
perform a series of "Hot‑Test" validations for quality control purposes. After the tests, the engine oil drains back into the pan
and loses its lubrication value for the bearings, valve‑train, and cylinder walls. As shipped, the remanufactured engine or
longblock is therefore presumed to be dry.
IMPORTANT: This oil priming procedure is required for all remanufactured engines (including longblocks) prior to initial engine
start‑up to reduce the potential for premature bearing failures. Evidence of non‑compliance could result in the denial of a
warranty claim.
There are two methods to prime an engine prior to ignition. Although one is preferred, either may be used.
1. Prime using an engine oil priming tool (available at automotive parts stores; obtain locally). This is the preferred method.
2. Prime using a remote starter switch.
Remote Starter Switch 91‑ 52024A 1
Using an Engine Oil Priming Tool

1. Fill the engine crankcase to the proper level with the recommended synthetic blend engine oil.

Tube Ref No. Description Where Used Part No.
25W-40 Synthetic Blend
139 4-Stroke Marine Engine Engine crankcase 92-8M0078629
Oil
2. Remove the complete distributor assembly, being certain to mark it for proper reinstallation. Refer to the applicable
MerCruiser Service Manual for details.
3. Install the oil priming tool into the distributor bore and onto the oil pump shaft.
4. Rotate the oil pump with an electric drill until oil pressure registers on an oil pressure gauge. Oil pressure will typically
register within two minutes of running the drill.
5. Remove the priming tool and reinstall the distributor according to instructions provided in the applicable MerCruiser Service
Manual.
Using a Remote Starter Switch
1. Fill the engine crankcase to the proper level with the recommended synthetic blend engine oil.

90-8M0149179 eng NOVEMBER 2018 © 2019 Mercury Marine Page 8B-11