Gear Housing Noise; Drive Shaft Housing Noise - Mercury BRAVO Service Manual

TROUBLESHOOTING

Gear Housing Noise

Metal particles in drive unit lubricant.
Propeller incorrectly installed.
Propeller shaft bent.
Incorrect gear shimming.
Worn or damaged gears and/or
bearings caused by impact,
overheating or improper shimming.

Drive Shaft Housing Noise

Engine flywheel housing contacting
inner transom plate or exhaust pipe.
Propeller with untrue or out-of-balance
blades.
Abnormal sterndrive operation.
U-joint cross and bearing assembly
retaining rings improperly installed or
of incorrect size.
Excessive side-to-side play in U-joint
cross and bearing assemblies.
U-joint bearing caps contacting U-joint
bellows retention sleeve.
U-joint cross and bearings rough.
O-rings missing or flattened out on
U-joint shaft causing shaft to rattle
against ID of gimbal bearing.
Page 1C-4
Cause
Cause
SERVICE MANUAL NUMBER 28
Special Instructions
Disassemble, clean and inspect and
replace necessary components. (Refer
to SECTION 3B, 3C or 3D)
Inspect mounting hardware. Install
propeller correctly.
Inspect and replace if necessary.
(Refer to SECTION 3B, 3C or 3D)
Check gear housing backlash and
pinion gear height. (Refer to SECTION 3B,
3C or 3D)
Disassemble, inspect and replace. (Refer
to SECTION 3B, 3C or 3D)
Special Instructions
Determine cause for interference
(loose engine mounts, transom too
thin, etc.) and correct as necessary.
Repair or replace, as required.
Instruct operator on proper operating
technique.
Make sure that proper thickness
retaining rings are used and that rings
are fully seated in u-joint bearing cap
grooves. (Refer to SECTION 3A)
Replace cross and bearing assembly.
Make sure proper cross and bearing
assemblies are used. If interference is
severe, replace cross and bearing
assembly and / or sleeve assembly.
Replace assemblies. Signs of scoring,
galling or roughness are the result of lack
of lubricant. (Refer to SECTION 3A)
Install new o-rings. (Refer to SECTION
3A)
90-863160 MAY 2000