Technical help for Do-it yourself boaters.

We hope to provide useful information for boat owners with MerCruiser, OMC, and Volvo Engines and Sterndrives. Many weekend ending problems encountered by boaters can often be prevented by regular maintenance and a basic knowledge of how things work. Expensive marina charges and a fear of the unknown sometimes combine to allow small problems become ignored resulting in expensive major failures. My partner and I each have well over 20 years experience in the Marine repair business. We hope to help educate the do-it yourselfers and promote the recreational boating industry. We will be publishing some guides for some common repairs and maintenance. Please read disclaimer below.

Recommended Basic Maintenance intervals:

Before each use:

• Check engine compartment for fuel vapors: Use your nose or a fuel vapor detector.
• Verify proper fluid levels: Oil, gear lube, power steering, transmission (if equipped)
• Check and or clean flame arrestor: Wipe off dirt and oil film. This can be a fire hazard if not performed. Watercraft officers can and do issue citations for dirty flame arrestors.

Every 50 hours:

• Change Engine Oil and filter: (some may recommend every 100 hours, your application may vary) This is one of the most important procedures for the life of your engine. If you only change oil once a year do it in the fall, dirty engine oil will eat away at internal parts all winter. 
• Check battery electrolyte level: Onboard charging systems may "boil" electrolyte out of battery(s) in as little as a week. Batteries older than 3 years should probably be replaced.
• Check for loose, missing components: The Engine and water produces tremendous vibration. Batteries should be well secured. Wiring and fuel hoses should not be allowed to chafe on or touch hot engine components.
• Check all electrical connections: Loose battery terminals can cause sparking and a potential fire hazard. Bad connections also promote corrosion.
• Inspect propeller for damage: Bent or damaged props will cause vibration, cavitation, and eventual sterndrive damage.
• Check cooling system hoses: Check for cracked, brittle hoses which can cause overheating or sink the boat.
• Check exhaust system components: Check for leaks or rust marks indicitive of leaks, corroded exhaust manifolds and elbows can allow water into the cylinders or or worse yet carbon monoxide into the boat.

Every 100 hours:             

• Replace water seperating fuel filter:   This is spin on filter on most models.      
• Check engine alignment:  This verifies proper alignment between the sterndrive and the engine coupler, incorrect alignment causes premature wear of the coupler. The engine must be removed to replace the coupler.                        
• Check and/or replace engine accessory belts:  Alternator, water circulating pump, seawater pump (if equipped).                                    
• Grease sterndrive U-joints: Sterndrive must be removed to grease U-joint shaft u-joints and grease input shaft with spline grease.                        
• Change gear lube:  Drain and replace gear lube checking for water, metal, or other contaminents. Most manufacturers recommend synthetic gear lube.                                    
• Inspect zinc anodes, replace if necessary: "Zincs" (can be magnesium, zinc, or bare aluminum) help protect aluminum parts from corrosion by "sacrificing" themselves, rule of thumb is to replace them when 50% depleted. anodes are not effective if oxidized, clean or replace them.
• Lubricate shift, throttle, and steering pivot points: Good quality marine grease.
• Replace tune-up parts: electronic ignition parts can last longer but the parts are relatively inexpensive. Keep spares.
• Lubricate propeller shaft: Propshaft should be kept lubricated to keep prop from becoming frozen. Check propshaft for fishing line which can get wrapped around and cut seals.

Every 2 years*:

• Replace seawater pump impeller: Seawater pump is located in the sterndrive lower unit on MerCruiser Alpha One (generation one, two, and older models). OMC cobra seawater pump is located on the upper unit. Volvo sterndrives as well as the newest OMC models have the seawater pump on the engine. MerCruiser Bravo, ll TR/TRS models also use an engine mounted seawater pump.

*  Some conditions such as sandy or very brackish water may require seawater pump replacement every year, this is especially true with alpha one generation two sterndrives.

 

Every 3 years:

• Replace gimbal housing rubber components: Bellows, water hoses, shift bellows, etc. These components protect vital (read; expensive) mechanical parts and keep the boat afloat. A leaking bellows will allow water to destroy the U-joints, gimbal bearing, and allow water into the drive's gear lube. This can also sink the boat.

***By no means is this a comprehensive list or in no way should these tips replace the manufacturer's recommendations or the prudent advise of a professional technician. Some procedures can be potentially hazardous, Al's Marine Service (alsmar) and or dockpartner.com cannot be held liable for damages or injuries resulting from incomplete, incorrect, or unspecific information. By all means individuals performing mechanical procedures should acknowledge and eliminate any potential risk and consult the appropriate service manuals or a trained professional.