As summer approaches, it’s time to start thinking about the upcoming fishing season. Maintaining your engines, marine gears, and generators should be on your annual de-winterization to-do list. A proper maintenance plan is vital to not only maximizing your fishing time and enjoyment this season but to extend the life of your engines as well. Following your manufacturer’s recommended maintenance program will help to ensure your days on the water are worry-free.

Equally important is understanding the operating parameters of your engines, and knowing how your engines and their systems work will help you identify problems early on, preventing small issues from becoming significant failures that keep you at the dock while the fish are biting.

All modern diesel engines have similar needs: clean air, clean fuel, and good, quality lubricating oil and coolant. Other than these basic needs, today’s engines vary significantly from one manufacturer to another and from one model to another regarding maintenance specifics. Oil change intervals, quantity and quality of oil, chemistry, and volume of coolant and filtration specifications vary widely based on each model’s configuration, operating pressures, and system components. Therefore, it is especially important that you are familiar with your manufacturer’s recommendations, specific to the exact model of your engine, for each maintenance activity.

Work with your service provider to stay on top of these common diesel engine maintenance items:

1. Change engine and marine gear oil and oil filters:

  • Follow the engine manufacturer’s recommendation for service intervals.
  • Engine oil is usually changed every 200-250 hours, or once a year depending on the category of oil used.
  • Some marine gears do not have oil filters; they have a cleanable screen element. Be sure to clean this element at the time of oil change.

2. Change your primary and secondary fuel filters:

  • Always change your primary and secondary filters at the same time.
  • Failure to service your fuel filters can lead to poor engine performance and engine smoking.

3. Analyze oil and coolant:

  • The service life of the engine oil may be optimized by regular laboratory analysis performed in consultation with your engine service provider. Oil and coolant samples should be taken and analyzed at least once per year, during each oil change, and under certain conditions. Depending on the application and the engine’s operating conditions, sampling/analysis may need to take place more frequently. After completion of all analyses, and depending on the findings, your service provider can make recommendations to enhance engine performance.

4. Inspect and replace, or clean the engine air filters:

  • Paper elements cannot be cleaned and should be replaced at or before the manufacturer’s recommended interval.
  • Cleanable air filters (AirSep, etc.) should be cleaned and oiled no more than four times before replacing.

5. Change zincs on your engines and marine gears:

  • Inspect or replace your zincs at every service interval.
  • Make sure that you remove all of the old zinc. Not doing this could lead to a restriction of the raw water system.
  • Note: Depending on the metallurgical makeup of the individual components in your engine’s cooling system, your engine or marine gear may or may not include sacrificial zinc anodes in the raw water side of their respective cooling systems. You should make sure you know what your engine and gear cooler require.

6. Perform the manufacturer’s recommended valve adjustments:

  • Follow your engine manufacturer’s recommendations.
  • Failure to perform recommended valve adjustments could lead to poor engine performance.

7. Check or replace your engine’s coolant as recommended:

  • Follow your engine manufacturer’s recommendation.
  • Mixtures of various coolant additives and supplementary additives are not recommended.
  • For corrosion-related reasons, it is not recommended to operate an engine with pure water without the addition of a manufacturer-approved corrosion inhibitor or coolant mixture, unless it’s an emergency.
  • Manufacturer recommended coolants/inhibitors should be premixed with suitable fresh water prior to topping up coolant levels.
  • Note: Failure to maintain your cooling system or using coolant that does not comply with the manufacturer’s defined specifications could result in poor heat transfer and deterioration of internal cooling system components (piping, housings, etc.).

8. Inspect relief bores (weep holes) in the freshwater pumps and raw water pumps:

  • Clean out any obstructions. Failure to do this could cause a leaking shaft seal to not leak out of the weep hole, but into the engine crankcase, which could lead to an engine failure.

9. Inspect or replace engine belts:

  • Replacing worn or cracked belts will help reduce downtime.
  • If applicable, inspect belt auto-tensioner for freedom of movement.

10. Keep accurate records each time you operate the engines:

  • The best way to build a specific knowledge base for the engines in your boat is to keep a detailed log of the engine’s activity. Also, keep a log of the locations where the boat has been run. Whether it’s down south with much warmer seawater and ambient air temperature, or up north with cooler temperatures, engine temperature and performance can vary in different conditions.
  • Keep a log of engine and marine gear pressures and temperatures at various RPM’s. Also be sure to log engine load and fuel burn percentages at the various speeds.
  • Know the operating range defined as normal by your manufacturer for the above factors. Historical knowledge of how your engines run will allow you to notice slight deviations and detect impending problems with your engine’s systems.
  • Apply the same logic to engine oil and coolant analysis. Comparing a baseline analysis to the trend line of subsequent analyses will give you an idea of the changing chemistry in your oil and coolant, and an indication of what is going on within the components of your engine.

Bottom line, the formula for good maintenance and successful boating isn’t complex or difficult.

  • Understand and follow your specific manufacturer’s recommendations for your engine model.
  • Log the activity and operating conditions for your engines and know the normal range for your engines.
  • Perform oil and coolant analyses and service following recommended schedules. Track the results and compare them to previous analyses.

Good fishing from your team at Johnson & Towers and Western Branch Diesel