Rinsing Fuel Tank Top

A conversation among Whalers
JTC
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Rinsing Fuel Tank Top

Postby JTC » Tue Mar 20, 2018 9:59 am

The manufacturer of my other boat, Grady-White, recommends periodically opening the access hatches and rinsing the top of the fuel tank to prevent salt build-up and resulting corrosion. Do any readers [periodically rinse the top of their Boston Whaler boat fuel tank]?

jimh
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Re: Rinsing Fuel Tank Top

Postby jimh » Tue Mar 20, 2018 10:06 am

I do not periodically rinse the top of the fuel tank in my Boston Whaler boat. There are several reasons why I don't:

  1. boat is used in fresh water so no concern with build-up of salt
  2. no access by an opening hatch is available to the top of fuel tank
  3. fuel tank is contained in a cavity which does not drain

Jefecinco
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Re: Rinsing Fuel Tank Top

Postby Jefecinco » Tue Mar 20, 2018 7:06 pm

No, although our 190 Montauk has an access plate above the tank, we boat exclusively in salt water, and the tank cavity drains into the bilge. I periodically open the access hatch to inspect the tank top paying particular attention to the fuel level sending unit but have not seen any sign of a need to rinse it. The tank is poly as are the tanks, I believe, in virtually all modern Boston Whaler boats with an installed below deck tank or tanks.
Butch

JTC
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Re: Rinsing Fuel Tank Top

Postby JTC » Tue Mar 20, 2018 10:33 pm

Interesting - for some reason I assumed [my 1996 20 Dauntless] had an aluminum tank. I'll have to look at it more closely through the inspection hatches.

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Phil T
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Re: Rinsing Fuel Tank Top

Postby Phil T » Wed Mar 21, 2018 8:01 am

With the exception of the V20 and 1979-1980 model years of the Revenge, all models up to approximately 2005 had aluminum under-deck fuel tanks.

CGPD models may or may not be the same as their civilian brother-sister since they were custom built for each customer.
Member since 2003
1992 Outrage 17, 1992 Evinrude 115

Jefecinco
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Re: Rinsing Fuel Tank Top

Postby Jefecinco » Wed Mar 21, 2018 9:19 am

Phil--our 1999 Dauntless 16 purchased new in March 1999 had a poly under the deck fuel tank. I believe poly tanks were in wide use by Boston Whaler well before 2005.
Butch

Whalerdog
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Re: Rinsing Fuel Tank Top

Postby Whalerdog » Thu May 10, 2018 7:30 pm

Yes [to the question about rinsing the top of the fuel tank].

[The top of the fuel tank] gets scum and mold in there.

gobuck
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Re: Rinsing Fuel Tank Top

Postby gobuck » Fri May 11, 2018 9:55 am

[In reply to the implicit question about what models of Boston Whaler boats in what years had fuel tanks from what materials]: my 1999 Outrage 17 had an aluminum tank. I just replaced the aluminum tank.

barry59
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Re: Rinsing Fuel Tank Top

Postby barry59 » Mon Jul 09, 2018 11:18 pm

[In reply not to the question about rinsing the fuel tank top, but on a new topic of what sort of sprays might be used to suppress corrosion on outboard engines and on electrical connections:} Mercury makes a paraffin-based spray for engine and electrical corrosion resistance.

If a [fuel] tank (or anything else) is clean, then [unspecified parafin-based spray made by Mercury] spray may help avoid corrosion. I swear by it for my saltwater engine, and I have had great luck avoiding engine corrosion on the exterior of motors and electrical parts.

jimh
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Re: Rinsing Fuel Tank Top

Postby jimh » Tue Jul 10, 2018 1:43 pm

On every Boston Whaler boat that I have ever seen that has an ALUMINUM fuel tank, the aluminum fuel tank has already been painted or treated or plated with a corrosion resistant top coat. Based on the green hue of the color of the top coat material, I believe the top coat is some sort of ZINC-CHROMATE of perhaps ZINC-PHOSPHATE paint primer. Such primers are used extensively to treat aluminum to prevent corrosion, and have been used for decades.

The notion that in addition to the already treated aluminum with corrosion-protection top coat would need to be further augmented with some sort of wax spray is a reasonable notion, but if that sort of treatment is desired, I would just use a widely recognized product from the aircraft industry, called BOESHIELD T9 in preference to any unnamed parafine-based spray made by a particular outboard engine manufacturer.

The problems in trying to follow advice to treat the fuel tank with further top coats:

--the tank is already in place, and only a small portion of the tank surface can be reached
--the tank is foamed in place, and much of the surfaces that are visible have foam on them.

Again, as a corollary topic to the actual topic--do you rinse the top of the fuel tank--I don't find recommendation to apply further anti-corrosion top coats to the tank to be particularly mandatory. Also, in many cases, corrosion-protection material actually work by forming a layer of oxide, and it is the creation of that extra layer of oxide that protects the underlying layers from further corrosion.

In general, I don't think it is always a good plan to try to out-guess the OEM manufacturers about what is the best protection. I would expect that if Boston Whaler thought that spraying the top of their fuel tanks with a paraffin-based spray after many years of use of the boat was a good idea or represented an effective way to reduce corrosion of the aluminum, then they would probably have recommended it.

The notion that Mercury makes such a spray suggests to me they probably recommend it for their outboard engines. You'd think Boston Whaler would then--being another Brunswick brand--also recommend it for their fuel tanks, if it were an effective treatment.

Royboy
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Re: Rinsing Fuel Tank Top

Postby Royboy » Tue Jul 10, 2018 3:30 pm

I rinse the fuel tank compartment if it gets saltwater in it, which it sometimes does if somebody bumps the bilge pump switch off the "auto" position. (I really must wire the bilge pump float switch to always on). I have a 1999 Outrage 17 and it has an access hatch at the helm and a drain in the fishbox. My tank has been replaced with a fabricated stainless steel tank and I want to make sure it never needs another replacement.

dtmackey
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Re: Rinsing Fuel Tank Top

Postby dtmackey » Tue Jul 10, 2018 10:43 pm

Aluminum tanks corrode over time and most manufacturers foam the tanks in to prevent them from moving. Not sure about Whalers for drainage, but I would never rinse a foamed in tank or a tank that has cavity that has questionable drainage, as the moisture sits inside the coffin cover where the tank is. Most tank companies that build replacement tanks offer coal tar epoxy coating and that is the ideal solution to protecting a tank. I redid my tank 12 years ago with zinc chromate primer and bedliner spray and it's now 28 years old in a sealed foamed in coffin.

D-

Acseatsri
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Re: Rinsing Fuel Tank Top

Postby Acseatsri » Tue Jul 17, 2018 11:24 am

The problem here is that when a tank fails, it's almost always corroded from the inside out, usually at the lowest rearmost point where water and perhaps phase-separated ethanol sit.
I've seen a few tanks replaced, including my own that had the same pinhole that wasn't visible, even with the tank out of the boat, until the gas showed a tiny wet spot in an otherwise perfect looking tank that was painted from the outside with some kind of coating.