Extra fuel tank, need your input

[Blue_Runner]

I have an older 18 - 20 gallon tank, possibly Moeller, unsure of mfg. It is a below deck tank and I would like to modify it to use above deck to extend the range on the V21 which has the 60g below deck tank. The dimensions allow my spare tank to fit perfectly under the bench seat. The tank would be used on the way to the fishing grounds so weight is only an issue for the first couple hours. The idea is to be able to make 125 -130+ mile round trips more doable and comfortable. I found a pic on THT where someone already did just what I am trying to do. I have all of the parts I need, fuel pickup, elbow, fill cap, fill hose, clamps, etc. but trying to figure out the fuel vent. I'm worried that such a short height on the vent as pictured might allow fuel to jostle out in while underway. Another concern is making sure spray, rain water, etc. stays out of the vent.

Last year I started carrying two 5 gallon cans which allowed us to come in with just under a half a tank reserve in the V21 (25 gallons) on a 45 mile run one way and a lot of running and gunning while there. Pouring over the gunnel into the fill is a real PITA trying to hold 30lbs out there when the boat is rocking and rolling! The ledge where we fish is 55 - 60 miles. I want to make it doable on those awesome days....the ones we ever so patiently wait to come along. Thanks for any help/ideas fellas!

This is the picture I found on THT which shows almost exactly what I am trying to do:

[phatdaddy]

blue, could you replace the fill cap with one of the new ones that vent

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Vented Fuel Fills
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Chrome-plated bronze cap
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Stainless-steel bead chain
Integral tank vent with flame arrestor and anti surge-valve... read more
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edit: sorry, tried to paste pic on an ipad, not working

[Blue_Runner]

I actually thought about those but I didn't realize the vent had an anti-surge valve. I assume that means it won't let the fuel come out but lets air in right? Do you think I would I need to put a 5/8 hose on it or just leave it be as is? This seems like the perfect option because then I can just cap off the vent on the tank.

Trying to get some more range out of the old 2-smoke motor. With the extra tank I'd have 76 usable gallons multiplied by 2.3 mpg comes to 175+ range. The 2.3 mpg is a little conservative by the way. The round trip would be 140 miles or less so there is the safety reserve built in to the equation. I certainly don't want to be coming in on fumes!

[phatdaddy]

i think you still use the vent, but you connect the hose to the small outlet on the fill, the vent is through the cap.

[bradford]

Racor makes a "Lifeguard" fuel/air seperator that plumbs into the vent line. West marine wants $92 bucks for one which sounds pretty high. Might be worth shopping around for.

[phatdaddy]

that is like a check valve to prevent fuel from burping out of the vent. go to the west site and search for vented fuel fill, the have them for $46. new to the ipad, so can't paste a pic yet.

[SkunkBoat]

Originally Posted by Blue_Runner

Pouring over the gunnel into the fill is a real PITA trying to hold 30lbs out there when the boat is rocking and rolling! The ledge where we fish is 55 - 60 miles. I want to make it doable on those awesome days....the ones we ever so patiently wait to come along. Thanks for any help/ideas fellas!

I have been making 100+ mile trips also and carried extra 5 gals for "oh crap". Luckily I haven't come close to needing it with my four stroke. I have however considered adding a 3 way fuel valve with a plug/jack connection to a portable 6 gal tank. That would allow me to carry a portable tank and just plug it in and turn the valve to use it. No trying to pour it into the gunnel fill.
And it does not take away permanent space on the boat.
And you don't have to worry about the vent and fill.

[Blue_Runner]

Good thoughts guys I'll do some looking around. Skunk, I used a 3 way valve on the saddle tanks on the '73 so I know what you're talking about. The problem is 6 gallons alone won't do me much good. I'm needing 15 - 20 gallons with my 2 stroke and happen to have this tank laying around.

I've done 100+ mile trips with no extra tank and burned around 40 ish with 50 being the most ever burned. That was a little uncomfortable. I wouldn't mind being able to do a little trolling with my bottom trips since we are right there near the blue water anyway.

Will be looking around today.

[Blue_Runner]

Found this fuel vent surge protector. Installs in-line. Sounds interesting.
http://www.amazon.com/Attwood-Fuel-V.../dp/B0000AZ7PE

[Blue_Runner]

This looks like the vent I need.
http://shop.sportsmansguide.com/net/...FcyhOgodHl8AKA