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Midseason Boat Maintenance

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Performing just a few little summertime chores will make the rest of your season on the water hassle-free.

You’re a couple of months into this year’s boating season and you haven’t had any problems, right? So now, how about spending a few hours this weekend lavishing a little TLC on your boat’s onboard systems, just to make sure that the balance of the season is just as enjoyable and carefree as the days that have already motored off into the warmly remembered past.

ust a little TLC will keep your boat’s powerplant operating  smoothly. Midsummer is a great time for oil analysis.

Just a little TLC will keep your boat’s powerplant operating smoothly. Midsummer is a great time for oil analysis.

Regardless of whether your boat is powered by diesel or gasoline engines, you need to spend a few moments thinking about your fuel. More than likely, when you filled up this past spring, you either used a pretreated “boat fuel” such as ValvTect’s marine gasoline ( or you went with plain old fuel from a fuel dock or even a land-based station, but with an additive such as Star Brite Star Tron ( or Marine Formula Sta-Bil (

But consider this. Undoubtedly, you’ve topped off once or twice since then and, if you hit an unfamiliar fuel dock somewhere along the line, the quality and/or makeup of the fuel that’s in your tank right now may be iffy, especially given the ethanol issues that persist with today’s gasoline. So a little insurance in the form of some extra fuel additive is a good idea, eh?

For gasoline, Star Tron (a 32-ounce bottle costs $29.99 and treats 256 gallons) and ValvTect’s Ethanol Gas Treatment (a 32-ounce bottle costs $27.99 and treats 240 gallons) combat the effects of ethanol, especially the potential damage that can be caused by phase separation. When gasoline phase-separates, the alcohol and water in it split off and, if your engine takes in the water and tries to burn it, damage can occur. ValvTect adds an ingredient that neutralizes the ethanol in E10 and E15 fuels, making the gasoline usable for up to a year.

ValvTect’s product also has a moisture dispersant that helps keep water and fuel from separating and a detergent to clean up and remove deposits from the fuel-injection system. Star Tron is an enzyme-based treatment that disperses throughout a tankful of gasoline as sub-micron-sized droplets that are safely eliminated while the engine runs. It also removes and prevents gum, varnish, and carbon deposits. Marine Formula Sta-Bil stabilizes ethanol-enhanced fuels and has more than four times the fuel system cleaner and twice the corrosion preventer found in standard Sta-Bil. A 32-ounce bottle retails from $24.99 to $29.99, depending on where you buy it, and treats up to 320 gallons of gasoline.

For owners of diesel-powered vessels, Star Tron for diesels (a 16-ounce bottle costs $16.99 and treats 512 gallons) uses the same droplet approach to disperse moisture in diesel fuel and prevents bacteria without the use of poisons or biocides. ValvTect’s BioGuard Plus 6 additive (32 ounces treats 375 gallons and will run you $39.99 at West Marine) protects in some of the same ways, combining a biocide with a multifunctional ingredient to prevent bacteria, algae, and low-sulfur issues.

Regardless of the type of fuel you’ve been burning this summer, don’t forget about your fuel tank or tanks. Star Tron Tank Cleaner uses its enzyme formula to clean sludge and contaminants from gasoline or diesel tanks. A gallon bottle of the clear liquid prices out at $40 to $49 depending on where you buy it. Algae-X’s AFC-705 ( is a concentrated additive that you add to the tank to break down and dissolve sludge and organic debris and stabilize diesel or gasoline for up to a year. A $35, an 8-ounce bottle treats 320 gallons of fuel, while the 1-gallon jug treats 5,000 gallons and costs $235.

Extra additive will ensure your fuel is clean-burning and efficient.

A long-handled brush is a great way to help you save some money and time and keep the green, performance-busting slime off your boat’s bottom. I anchor my boat in about 3 to 4 feet of water and jump in. Then I scrub down from the waterline as far as I can reach with the brush. This removes a great deal of the slime from my hull bottom, helping to ensure that my boat is running as smoothly and as cheaply as possible. And yeah, I get a pretty good workout too.

Don’t Forget To Brush

But even fresh fuel in clean tanks can’t efficiently get to your engines through slightly obstructed or even clogged filters. While dockside, check the filter elements in your fuel/water separator or separators to make sure they’re not full of gunk. If you’re planning any extended cruises later this summer or fall make sure you know how to quickly replace an element or elements without air-locking an engine so you don’t get stuck in some remote area. And remember—it’s always a good idea to carry a jug of diesel fuel to top off filter canisters, should you have to do the job by hand. And always carry a bunch of extra filter elements for good measure.

Of course, clean oil is just as important as fresh fuel. And as the summer wears on, you should probably have your yard take an oil sample and send it out for analysis. Florida Engine Surveyors (, just one of many analysis companies around the country, performs oil spectrometer analysis ($45 to $50 per sample) to identify a variety of maladies including metal wear, cooling-system leaks, blown gaskets and O-rings, and more. If you’re comfortable working on stuff in your own engine room, take your own sample with the AMSOIL Oil Analyzers Test Kit (; $32.50). The postage is prepaid and AMSOIL will promptly send you the results in the mail.

Once you’ve dealt with petroleum-based fluids during your mid-season maintenance extravaganza, there are a couple of other things you might address. First, how about your fresh water? Many people use household bleach in various ratios (1 tablespoon per gallon of water is a good rule of thumb) to purify their freshwater tanks and then flush the system through all the faucets in the boat. But bleach can be corrosive and it’s tough to get both it and its chlorine-like aftertaste out of a water system. Aquabon Drinking Water Freshener ($14.99 at West Marine), on the other hand, has earned great reviews and is easy to use. Just pour it into your freshwater tank at the recommended dosage and there’s no flushing required. You can also add Camco Taste Pure Fresh Tabs (from $5.99 to $9.99 for a pack of six tabs depending on your point of purchase). One tablet treats 15 gallons of water.

Then finally, there’s climate control. To keep your cool when the dog days of late summer come barking, make sure your air conditioner is working as efficiently as possible. Not only should the sea strainer be clean and debris-free, but the impeller on the raw-water pump should be standing proud, with all the vanes present, accounted for, and fully intact. While you’re at it, you might also inspect your air-conditioning system’s condenser coil. If it gets clogged or partly clogged, have it flushed out by a technician or maybe do it yourself. And for boats with chilled-water systems, make sure that the circulating water is flowing freely and all filter changes stipulated in your manual are up to date. And another good idea: Clean (with a vacuum cleaner) or replace the air filters on all your air handlers—dust does not facilitate efficient cooling.

Clean or replace the filters in your air conditioning system

Tired yet? I’ve got one last suggestion. With all this due diligence behind you, go out and enjoy the rest of your summer. You deserve it.

air-conditioning pump

This article originally appeared in the July 2013 issue of Power & Motoryacht magazine.