I have been asked many times what single maintenance issue has caused the most problems for our customers at Potter Performance Engines. That’s an easy one—lack of proper flushing is the single biggest issue we deal with on saltwater engines. We can always tell who actually flushes their engine and treats the cooling system correctly, and who simply claims to.

Failure to flush your marine engine after every use will ensure it fails you in the future (click image to enlarge). Photos courtesy/copyright Potter Performance Engines.

Salt in an engine is highly corrosive and everyone knows it. I can’t tell you how many engines we have torn down with rotted gaskets, cylinder heads, blocks, manifolds and so on. Proper flushing after every use is a must, and we recommend doing it for 10 minutes on a warm engine. We also recommend the use of products such as Salt Away, and Salt Terminator, to name a couple. Properly used every time, these products can make a tremendous difference in the lifespan of not only internal engine components but also pumps and exhaust systems.

We like our customers to use these products after flushing with freshwater first. You can never flush an engine too much. Just make sure you have an ample supply of water and don’t overheat your engine. We have several customers—with boats powered by our engines—who boat in saltwater exclusively. Many of these engines have aluminum cylinder heads and, believe me, aluminum heads and saltwater don’t mix.

Many years ago we had a customer who brought his Potter Performance 1,150-hp engines back for standard rebuilds. These engines had been running in the ocean for three years.

After we had the engines disassembled, I couldn’t believe the condition of the cooling systems. They looked like the engines had been run in freshwater. I contacted my customer and asked him what he was doing as we had never seen engines look so good after such intense use in saltwater. He told me that he had been using these products after standard flushing every time, and had been for years. Well, I was convinced. This stuff works. I won’t tell you this is the answer to all your corrosion issues, but it does make a big difference.

Ron Potter: “I can’t tell you how many engines we have torn down with rotted gaskets, cylinder heads, blocks and manifolds.”

Draining the cooling system completely can be a problem as well. Several years ago, we had a very good customer who had put his boat up for sale and let it sit for more than two years without use. He had the engines flushed and drained as he thought it was a good idea.

We received a call one day from the dealer who informed us there was a problem with one engine. After starting the engines for a potential buyer, he had steam blowing from the valve covers. The dealer sent us the engine and after inspection we found the cast iron cylinder heads were corroded through. We had him send us the other engines for inspection and they were deteriorated as well.

The problem is once saltwater has been in an engine and then you introduce oxygen, the corrosion process is accelerated. We tell all our customers, if you are not going to be using your boat for over a month, drain the cooling system and fill it with nontoxic or RV antifreeze. Disable the ignition, pour the antifreeze into the sea strainer and turn the engine over with the starter. It will take around three to four gallons per engine.

Leaving water alone in the engine for an extended amount of time can be as bad as exposing it to air. RV antifreeze doesn’t turn stagnant and we feel it helps to slow down the corrosion process. We have also noticed much less internal corrosion in engines where customers have used the RV antifreeze. This is also true of the exhaust systems.

I know this seems like a lot to deal with. But believe me, a little extra time spent with proper flushing and storage can save you a lot of money down the road.

Editor’s Note: This is engine builder Ron Potter’s second bi-weekly column for speedonthewater.com. He next installment will go live on Monday, Feb. 15.

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