Ask The Experts

Solutions from the BoatUS Tech Team

Photo of painting the trim

Where's The Proof?

I need to replace the starter on my 1989 Volvo 5.7L V8. There are many starters advertised as "marine certified," with prices varying from $50 to $500 or more. Is there a telltale way to verify that the starter in question is truly ignition protected? Will there be an ISO or SAE stamp on it? The reseller says, "Yes, it is ignition protected," but I would like to have some concrete proof.

Don Casey: There are standards of compliance that certify that an electrical item is ignition protected, namely SAE J1171, UL 1500, ISO 8846, and USCG Title 33CFR 183.410(a). All but the Coast Guard standard specify that the device meeting the standard must exhibit a marking or label, so a new starter intended for marine use should display one of these standards. However, if you are looking at rebuilt or reconditioned starters, then the original label is of unknowable validity. In this case your best assurance is likely to be to deal with a reputable seller and to make sure the invoice specifies"marine certified" .

Scavenger Hunt

I just purchased a 1997 Carver 280 express cruiser, with a gasoline engine. My problem is I cannot find a fuel tank vent anywhere on the hull. When I open the mid-berth closet, I can smell fumes. Is this a production error or is it vented some other way?

John Adey: According to the federal regulations, all components and connections of an inboard gasoline fuel system must be accessible, AND a vent system is required that will not allow any liquid overflow to enter the boat.

Knowing this, there must be a vent outside the boat and you must be able to access the fuel tank and vent connections. First, find the fuel fill, the vent may be on the same side but not immediately next to the fill. It should be a small fitting with the opening pointing down so water cannot enter the vent line. If you cannot find it outside, look in the cabin floor for an access plate that would reveal the hose connections and attempt to follow the hose to the exterior of the boat. Maybe a repair was attempted and the vent was never reinstalled?

This brings me to my next point, which is extremely important. You should never have a fuel smell inside your boat. This could mean several things all equally as dangerous:

1. A leak: This may be in the tank, hose, or fuel pump. This may be obvious (liquid fuel is evident) or may only happen when the boat is running. Either way, inspect and immediately tend to the problem.

2. Permeation: We blame ethanol for everything but one thing it can do is prematurely destroy older rubber hoses. If you can smell a strong gasoline odor from the hose itself, the fuel vapor may be permeating through the hose. This is extremely dangerous as fuel vapor is much easier to ignite than liquid gas.

3. Fuel in the wrong place: We have all heard and some have witnessed refueling "malfunctions" where 50 gallons is pumped into the holding/water tank or even a rod holder. Make sure what is supposed to be in all your tanks is actually what is in there! Similarly, make sure a portable fuel tank (jerry can or small outboard tank) is not stored inside the cabin or in a place with no ventilation. This is dangerous as well.

I do a semiannual fuel system inspection, at winterization and spring commissioning. Check every hose, joint, and fitting and make sure that vent is clear (once you find it). Every boat owner needs to know and be able to access and inspect all the major fuel system components, so take some time and go on a scavenger hunt, and please, do it before you use the boat again!

That #@&! Green Wire

I can't believe you experts don't see the folly of connecting AC ground to DC ground, breaking the electronics rule, "Don't mix grounds!" You can't convince me a current leak large enough to charge the water wouldn't kick a breaker, so why would you want to connect to all the other boats in the marina? Instead of buying an expensive isolator (nothing more than back-to-back diodes), just eliminate the problem, and don’t connect your outdrive or prop shaft to AC ground.

Don Casey: Your faith in breakers is misplaced. In seawater you are almost right, as saltwater is a decent conductor and enough current is likely to flow to trip a breaker. The same is not true in freshwater. Freshwater sailors are at extreme risk from boats that fail to connect the AC grounding wire to the DC ground. If you do any of your sailing in fresh water, I urge you to read this — — a numbing litany of swimmers suffering electric shock around boats and docks.

And before you discount those that do not involve a boat, keep in mind that dockside circuits are supposedly "protected" with the same kind of breaker you cite. What we have in fresh water is not a short in the sense of current flowing to ground. Rather, we simply have lethal potential, with a person becoming the conductor. Given that the preponderance of lake swimmers must surely be children, I cannot imagine a more heartbreaking scenario than being responsible for the death of a child — your child, your grandchild, the child of friends, any child. If you are concerned about being connected to the other boats in the marina, unplug your shorepower cord, but do not put risk of corrosion above the very real and far more serious risk of energizing the water around your boat.

Prime Time

We lose the prime on our new freshwater pump. Already replaced shut-off valves. We suspect a tiny leak that lets air in. We cannot find any place where water leaks out. Do you have any suggestions on how to test connections and lines for minor (air) leaks? Once I get it re-primed, the system runs well. It takes about 45 minutes to lose its prime again.

Tom Neale: You didn't say which type of pump you have, but I'm assuming it's typical to those commonly sold in marine stores, with three or more valves and a "wobble plate" arrangement. It isn't very unusual for a leak such as you describe to develop in one of the valves inside the pump. Essentially the little rubber flap isn't seating securely on the metal base. This is most likely to happen in older pumps because the rubber has gotten a little brittle with age, or because of trash, or in new pumps simply as a matter of bum luck. The water leaks back past the valve, resulting in symptoms just as you describe. The solution, if this is the problem, is to keep using it and hope the problem will work itself out, or if it’s an old pump, consider replacing the valve assembly (these are usually available at marine stores and aren't very hard to replace), or replace the pump.

If a replacement doesn't solve the problem, then there probably is a leak in the line somewhere between the pump and the tank. These are hard to find because there is a vacuum in the line when the pump is off and the leak is sucking air in rather than pushing water out. Before pressurizing the line, which would take quite a bit of effort, try very thoroughly checking the line until you find something. Another common place to check would be the strainer which should be before the pump. (If you don't have one, install one.) Sometimes the O-ring on these strainers becomes old or damaged and lets air in.

If you can't solve the problem, you can install a check valve just before the inlet to the freshwater pump. This should keep the water from "leaking" back to the tank.

Reaching Out

I have a 20.4 Angler walkaround boat with a stainless 3dB VHF antenna mounted on the T-top. The radio has never reached out very far, and I want to replace it. Should I go with a 3dB or a 6dB gain antenna? In rough weather, which I try to avoid, my boat rolls a bit. I am not clear on which should give me better performance, especially if I find myself in bad seas and I need to reach someone for help.

Don Casey: Gain is probably not your problem. On a T-top, the antenna is likely not much more than 10 feet above the water. The straight-line distance from that height to the horizon is about 3.7 nautical miles. Of course the other boat you are trying to raise also has an elevated antenna, but if it is also just 10 feet above the water, it, too, is going to "see" the horizon at 3.7 miles. Keep in mind that VHF radios operate on line-of-sight, so if these two boats are 8 miles apart, they are essentially on opposite sides of a hill of water, and communication will not occur. A 3dB antenna should have plenty of power to transmit eight miles, but the ocean is in the way. For boat-to-boat contact, one of you needs a higher antenna.

Ashore the Coast Guard might be transmitting from a 1,000-foot antenna, giving them a line-of-sight range of 37 miles. Add your range and you might talk to the USCG 40 miles out if your radio delivers enough power to the antenna to reach that far. More likely you will be able to hear them, but they won't hear you.

You are on the right track to change the cable first. Corroded and/or poorly installed connectors are the most common causes of loss of transmission power. Shamefully, too many installers also use the smallest coax — RG-58U — to save money. This is dangerous thrift when an emergency occurs. You need at least RG-8X coax. Stepping up to RG-213 will cut the power loss between radio and antenna in half, putting all that extra wattage into the air. Now the Coast Guard will hear you.

VHF radios are also very voltage sensitive, so make sure any voltage drop between the battery and the back of the radio is minimal — not more than 0.35 volt. Too often I see radios connected with undersized wiring, which destroys radio performance.

If you do change the antenna, you can get more range in benign conditions with a 6dB unit, but as you suspect, the narrower beam of this antenna is going to sweep over your target in rough conditions. This will result in a broken transmission at best. In a vigorous seaway, you will almost certainly be better served with the broader radiation pattern of a 3dB unit.

Hole Truth

I have a 1979 Endeavour sailboat and I need to clean out the thru-hull fittings. I had one closed with barnacles in it. Someone told me to spray muriatic acid into them. What is your opinion as to how to clean them?

Tom Neale: I would not spray muriatic acid into your thru-hulls. If you spray enough, this could get rid of the barnacles, but it could also impair the metal. Also, this is nasty stuff and could harm you and those nearby, particularly when you spray it. Airborne muriatic acid could be quite injurious. I use a kitchen knife, appropriately sized screwdriver, or carrot peeler and physically scrape loose the barnacles on my boat, taking care not to damage a hose or valve with the hard tool. I inspect my thru-hulls regularly in the water, and clean them if needed to avoid a bad buildup.

Beyond The Outboard

I had a 2002 150-hp outboard that kept slipping out of gear. Several supposed repairs later from a certified dealer, I decided to buy another outboard, this time a 2005 200-hp. The motor was used but the dealer said it was in perfect shape. I took it out once, with no problems. I ran it in storage three times with the appropriate water feeding the motor, and on the third run, it would not go into gear, just like the last engine. Comments? Is the manufacturer having a problem?

Tom Neale: While I can't diagnose the problem without seeing the engine and boat, your question is very important as it has broad implications for many of us, across the span of brands of outboards and engines, even though you're dealing with one specific brand. I spoke with Keith Whelan of Whelan's Marine in Farnham, Virginia. I take all my outboard problems to his shop. He said that he knew of no problems that your particular manufacturer was having regarding shifting. He suggested that if you have shifting problems on two different motors on the same boat, look away from the motor for the cause. Make sure you have a control specified by the manufacturer for the specific engine and cables specified for the engine, and that both are adjusted and operating correctly.

Hey Boat, Time to Get Up!

My 1989 Bayliner bowrider with a 120-hp engine and Cobra sterndrive has been covered and stored in my backyard since 2002. I am considering activating the boat this summer and was wondering, what is the best way to re-commission my Bayliner given that it was stored so long? Is there a publication of some kind to address this subject?

John Adey: I can't think of a single resource that will explain all of the things you may run into upon re-commissioning after 10 years! It depends on the extent of the winterization or storage procedures done. Here is my initial checklist before installing the battery and attempting to start:

1. Have a company remove any existing gasoline and replace with a small amount of high-octane fuel (that way, if it does not start, you won’t be looking at a huge amount of fuel). Change any fuel filters and inspect and replace fuel lines as necessary.

2. Drain and replace engine and lower unit oil.

3. Remove the spark plugs (careful to record the order), Loosen belts and spray some fogging oil in the cylinder and hand-crank the engine over with a socket wrench attached to the crank shaft pulley. (This could be an issue as the pistons could be seized to the cylinder wall).

4. Make sure the choke and throttle plates operate as intended (not stuck open/closed).

5. Reinstall plugs, tighten belts, connect battery, and attempt to start.

6. If it starts, consider replacing the sterndrive water pump and housing since it sat for so long. Also check for water in the lower-unit oil after the first use since seals tend to dry out over time. You can tell by a milky whitish color.

7. If anything goes wrong, consider writing me again!


I have a Chris-Craft Catalina 280. Do you know what the required zincs are on this vessel with a single inboard and trim tabs?

John Adey: This is not an easy answer! There are a couple of ways to go about this:

1. Have a corrosion survey done: There are ABYC-certified corrosion experts that can use a meter and tell you how much zinc to put on the boat and also look at your bonding system which helps protect all the underwater metals. abyc will give you a list of certified techs.

2. Observation: Do you have a problem now? Are similar boats in the marina OK, with no rapid zinc loss, corroded metals, etc.? Following their lead may be a good start. Where are their zincs located and how many are they using? Is there an owner's forum with practical experiences in your area?

3. Trial and error: Most boat owners take this approach, put on a few commonly available zincs in various places (prop shaft[s], rudders, trim tabs, etc.) If they are partially gone at the end of the season, all is good. The danger here is under- or over-protecting; not enough and your metals will suffer, too much and you could also do damage, often times in the form of "haloing" of the bottom paint.

Corrosion protection is individual for each boat and even geographic location. A galvanic isolator to keep other boats' stray current off your boat and knowing how much zinc your boat needs are two of the best strategies out there.  

— Published: June/July 2012

Meet the Experts

Photo of Don Casey

Don Casey
He's been one of the most consulted experts on boat care and upgrades for 30 years, and a panelist on our "Ask The Experts" website for a decade. He and his wife cruise aboard their 30-footer part of the year in the eastern Caribbean. His books include Don Casey's Complete Illustrated Sailboat Maintenance Manual, and the recently updated This Old Boat, the bible for do-it-yourself boaters.

Photo of John Adey

John Adey
The VP/Technical Director for the American Boat & Yacht Council (ABYC ), John grew up boating. He's been in the industry since 1990, with experience from a yacht brokerage and boatyard to owning a marine supply store. He and his family sail their classic 1976 Irwin ketch, a boat he completely restored. John is a trusted source for technical information for industry professionals.

Photo of Tom Neale

Tom Neale
He's maintained, lived aboard, and cruised long distance on boats with his wife and family for most of his adult life. He can take apart and fix almost every system aboard a boat, has written two books, filmed a two-set DVD on East Coast cruising, written for top marine magazines, and has won seven first-place awards from Boating Writers International and many awards for his technical writing.

Photo of Bob Adriance

Bob Adriance
The editor of Seaworthy, the damage avoidance newsletter of BoatUS Marine Insurance, Bob has written hundreds of articles on safety, loss prevention and causes of boating accidents. His 2006 book, Seaworthy, Essential Lessons of Things Gone Wrong, is based on 20 years of real claims files. He's owned Folkboats to J-Boats and currently sails a 36-foot sloop.


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