As a rule of thumb, most inboard engines should be serviced once per year or at the run time interval outlined in the manufacturer’s manual – whichever comes first.
Gasoline engines are typically every 100 hours and diesel will vary from 100-250 hours of run time. It is not necessary to change antifreeze every year as you would oil.
Should I change my impeller every year?
Some manufacturers recommend every other year or 1000-2000 hours. Some recommend every year.
We recommend you replace the impeller every year during an annual service to reduce the risk of extremely costly repairs. The water pump on your engine is its lifeline.
If it fails, your engine will be down, and the cost of the damages can potentially be in the tens of thousands of dollars.
I’m told that exhaust components should be inspected and changed regularly. Why is this and how often should it be done?
Just like your water pump is the lifeline of the engine, that water must leave the engine for the engine to be cooled down.
Marine exhaust differs from automotive because the water that is pumped through the engine to cool it off exits the engine through the exhaust.
Over time, your exhaust components, commonly referred to as the exhaust elbow, will begin to rust within the inside and will hinder the existing water flow. This will cause an overheat situation if not corrected.
The inner pipe carries the hot exhaust gases and the outer pipe carries the water. At the end of the exhaust elbow, the gases and water meet and exit the vessel through your exhaust hoses and mufflers.
We recommend inspection of the exhaust elbows every two years or 500 hours of use. Consider replacing every 5-6 years to keep your engine running as cool as possible.
Can my diesel cooling system be cleaned without removing the heat ex-changers?
Yes, it can. If you’re noticing your engine is running hotter than usual you could have clogged coolers.
Over time debris and marine life will find its way into the saltwater passages of the heat exchanger. This will hamper the saltwater flow and thus reduce the cooling efficiency of the engine.
This practice is typically called a “descale” and is mainly performed on closed cooling systems. A low acidic solution is circulated through the raw water-cooling system for a couple of hours and then flushed with fresh water.
Some use muriatic acid as it is a much cheaper chemical but this can be very harmful on your engine. This can erode the inside of the heat exchanger letting saltwater enter the antifreeze side of the cooling system and is not recommended.
Exhaust parts are so expensive! Is it necessary to replace them?
This really depends on the environment the vessel is in.
Freshwater vessels will have virtually no issues with rusted exhaust elbows, at least not the rate that saltwater will.
Saltwater vessels will experience this problem more frequently.
Failure to replace exhaust components, especially on gasoline applications, can lead to engine problems by water ingestion or overheating.
Over time the rusted exhaust elbow will begin to crack inside, and water will seep down the elbow and into the manifold and will rust out the exhaust valves and go into the cylinder.