Mercury Machine, a subsidiary of the Brunswick Corporation, manufactures MerCruiser engines, along with sterndrives and inboard motors for recreational and commercial boats of varying sizes and degrees of power. Boat mechanics can be complex, and it may be necessary to service your MerCruiser as part of routine maintenance or due to some mechanical defect.
Inspect the bellow hoses on the drive shaft to check for signs of wear and decay. Check for rust around the clamps holding the hoses to the shaft.
Lubricate the drives with lithium grease. MerCruisers usually have four drives. Keeping them lubricated ensures that they can move smoothly and won't rust or jam up.
Connect a multimeter to the stern drive and a ground (a water pipe, for example) to check the electrical system.
Replace the accelerator pump if your boat accelerates in fits and starts. The accelerator pump provides fuel to the carburator but its rubber piston can degrade over time.
Insert an alignment tool in the drive coupler to check the engine alignment. If it's misaligned, have it professionally serviced.
