Maintenance Schedule-Towsport Models; Routine Maintenance; Scheduled Maintenance - Mercury MerCruiser Service Manual

Task Interval
Every 100 hours or
annually
(whichever occurs first)
Every 300 hours or 3
years
(whichever occurs first)
Every 5 years
Maintenance Schedule—TowSport Models

Routine Maintenance

NOTE: Only perform maintenance that applies to your particular power package.
Task Interval
Each day start
Each day end
Weekly
Every two months or 50
hours

Scheduled Maintenance

NOTE: Only perform maintenance that applies to your particular power package.
Task Interval
25 hours
90-8M0099748 eng DECEMBER 2015
• Touch up the paint on the power package.
• Change the engine oil and filter.
• If the condition of the spark plugs, spark plug wires was satisfactory at the initial inspection (as
listed in Every 300 hours or 3 years), inspect the condition of these components every year
and replace as necessary.
• Inspect the water‑separating fuel filter and replace if debris is visible.
• Check the crankcase ventilation hoses and inspect the PCV valve, if equipped.
• Inspect the condition and the tension of the belts.
• Check the coolant level and antifreeze concentration for adequate freeze protection. Correct if
necessary. Refer to the Specifications section.
• Change the transmission oil and filter where applicable. This should be done once a year or
every 300 hours, whichever comes first.
• Inspect the exhaust system components. If the package was equipped with water shutters
(flapper valves), verify that they are not missing or worn.
• Clean the flame arrestor.
• Check the engine mounts for tightness and tighten to specifications if necessary.
• Inspect the condition of the spark plugs, spark plug wires. Replace as necessary. If the
condition of these components is satisfactory at inspection, repeat inspection every 100 hours
or once a year, whichever occurs first.
• Check the electrical system for loose, damaged, or corroded fasteners.
• Check the cooling system and the exhaust system hose clamps for tightness. Inspect both
systems for damage or leaks.
• Disassemble and inspect the seawater pump and replace worn components.
• Clean the seawater section of the closed‑cooling system. Clean, inspect, and test the
pressure cap.
• Replace the vent valve on each exhaust elbow (port and starboard).
• Replace the coolant/antifreeze. Replace every two years if not using extended‑life coolant/
antifreeze.
• Check the engine oil level. You can extend this interval based on experience with the product.
• Check the transmission fluid level.
• If operating in saltwater, brackish water, or polluted water, flush the seawater section of the
cooling system after each use.
• Check the water inlets for debris or marine growth.
• Check and clean the seawater strainer, if equipped.
• Check the transmission fluid.
• If operating in saltwater, brackish water, or polluted water, apply Corrosion Guard to the
power package.
• Check the battery connections and the fluid level.
• Ensure that the gauges and the wiring connections are secure. Clean the gauges. If operating
in saltwater, reduce this interval to every 25 hours or 30 days, whichever occurs first.
• Change the transmission fluid. Models equipped with a transmission filter must also have the
filter changed at this time.
Maintenance to Be Performed
Maintenance To Be Performed
Maintenance to Be Performed
© 2016 Mercury Marine
Maintenance
Page 1C-5