Re: How much Stern Fluid Usage is normal? 1 x 300-hp MerCruiser 350 MAG MPI Bravo III
You didn't mention if this was a new Bravo unit, but here is a service bulletin if it is:
Service Bulletin
Bulletin No. 2010-63
CMD Bravo Sterndrive Fill Procedure and Lube Level Drop During
Break In Period
Models Affected
All Bravo Sterndrives
Situation
MerCruiser has received reports of a drop in the level of gear lube after the sterndrive is first put into service.
Air trapped in the top of the driveshaft housing during the initial filling of the sterndrive may escape through the gear lube monitor during the break in period (first 20 hours of running time). As the trapped air escapes, the gear lube level in the monitor bottle drops.
New installations may require as much as 470 mL (16 fl oz) of gear lube added to the monitor bottle during the break in period (20 hours of running time). It is important to monitor and maintain the gear lube level during the break in period. If fluid is still required after the break in period, refer to CMD Service Bulletin 2010-04.
Action:
Check the gear lube monitor at the beginning of each day when the engine is cold. Fill as needed. If the gear lube alarm sounds during operation, add the appropriate amount of gear lube to the monitor bottle.
Tube Ref No. Description Where Used Part No.
87 High Performance Gear
Lube Gear lube monitor 92-858064K01
NOTICE:
Discharge of oil, coolant, or other engine/drive fluids into the environment is restricted by law. Use caution not to spill oil, coolant, or other fluids into the environment when using or servicing your boat. Be aware of the local restrictions governing the disposal
or recycling of waste, and contain and dispose of fluids as required.
Checking:
IMPORTANT: The gear lube level fluctuates during operation. Check before starting, when the engine is cold.
1. Check the gear lube level in the monitor bottle. Maintain the gear lube level within the recommended operating range. Refer to Filling.
CMD Bravo Sterndrive Fill Procedure and Lube Level Drop During Break-In Period
2. Inspect the gear lube condition. If any water is visible in the bottom of the gear lube monitor, if water appears at the fill and drain plug hole, or if the gear lube appears discolored, these conditions can indicate a water leak in the sterndrive.
Gear lube level shown in the correct operating range
a - "ADD" mark
b - "OPERATING RANGE" mark
IMPORTANT: If water is visible in the bottom of the gear lube monitor or appears at the fill and drain plug hole, or if the gear lube appears discolored, the sterndrive may be leaking.
Filling:
IMPORTANT: The addition of more than 470 mL (16 fl oz) of gear lube during the break in period may indicate that the sterndrive is leaking.
1. Remove the gear lube monitor cap.
a - Gear lube level at the "ADD" mark
b - Gear lube level at the "OPERATING RANGE" mark
c - Gear lube monitor cap
2. Fill the monitor with the specified fluid until the gear lube level is in the operating range. Do not overfill.
Tube Ref No. Description Where Used Part No.
87 High Performance Gear
Lube Gear lube monitor 92-858064K01
3. Ensure that the rubber gasket is inside the gear lube monitor cap.
4. Clean and install the cap. Do not overtighten.
Warranty:
This service bulletin is informational only.
