Newbie needs fuel tank help!!

[gdavies07]

I recently purchased a 1980 Grady White Tarpon 190 with an 87 Evinrude 140 VRO. (Still using VRO system) The previous owner put 10 gals of fuel in the tank to run it for me before purchase. The motor cold started great and idled great, etc. He purchased the package to steal the motor for his other boat but decided it was far too nice of a boat to take the motor from and dispose of the boat. He said he flushed the tank and it seemed fine. I expected there to be problems with the tank given its age so I don't feel that I got burned on the sale...
So I got it home and went to clean the built up leaves out of the bilge. Strong odor of gas!! When I tried to prime the bulb, it would not build pressure but I could hear what sounded like sloshing. Today when I squeezed the primer bulb I got nothing, like its sucking air. So the 10 gals that the PO had put in had drained from the tank I assume.
Now where do I go with things??? The tank is easily accessible, 6 screws in the deck to remove the access cover. (1 screw is crooked, and deck access has been resealed with clear silicon so I'm assuming it has either been replaced or tested). I'm on a budget so..
1) What are the benefits of the plastic belly tanks?
2) What gal tank should I replace it with if I was to replace it? Meaning my primary use for the boat is to fish.. 40 gals seems like alot of gas to sit unused between fishing trips (maybe 1-3 times a month if I'm lucky).
3) I'm thinking of using a portable tank instead (12 gal). Is that too little gas for a boat and motor of this size? What should I expect this motor to consume for fuel?

4) MOST IMPORTANTLY: What is the PROPER/SAFEST way to remove this tank if I decide to? I don't want to blow myself up!! Keep in mind the tank is currently empty with fuel recently being in it.. Meaning I'm removing a potential vapor bomb!!

 

[smokeonthewater]

Re: Newbie needs fuel tank help!!

If you run full throttle you can figure on emptying that 12 gallon tank in about an hour.... at best cruise on plane, two hours or so.

I'd think 30 gallons would be minimum. as for the vapors I'd pull the access panel and the leaky tank. I'd then use engine degreaser and a garden hose on the bilge along with scooping out any crud I found.

 

[smokeonthewater]

Re: Newbie needs fuel tank help!!

as for #4 use hand tools and don't smoke

 

[Home Cookin']

Re: Newbie needs fuel tank help!!

I have an in-hull tank and when I squeeze the bulb it sounds like it's pumping air, but it's fine. The bulb doesn't get rock hard. Now, you might have a small gas leak somewhere to fix, perhaps a connection.

 

[gdavies07]

Re: Newbie needs fuel tank help!!

I pulled the tank today and it looks like its remarkably in good shape for a 30 year old tank. I don't have any means of pressure testing it. Am I correct to think that I can empty the fuel and fill it with water to see where it might leak from? There was about 5 gals of fuel in it still. Welds looked good.
Why does that happen Home Cookin? I'm used to portable tanks primer bulbs firming up. Is there a reason why they dont in an inboard tank? I thought they had a one way check valve. Shouldn't they firm up? Today before I pulled the tank it sounded like it was just sucking air like you mentioned. A couple days before it made a gurgling sound. I figured after 30 years it was probably time to replace it anyhow.
There was a half gallon of liquid in there, either water or gas so I will seal it up good. The fill and vent hoses will need to be replaced. There was a transparent jelly on the hose close to the filler neck and vent. Is this from fuel leaking? Bacteria? Did someone put it there? It looked and felt like a jellyfish.

 

[smokeonthewater]

Re: Newbie needs fuel tank help!!

the squeeze bulb will do the same thing whether it is hooked to a portable tank, a mounted tank or the hose is dropped into a coffee can... if it isn't getting firm then either you aren't getting fuel or the bulb isn't working 100%

EDIT: while you're in there replace ALL of the fuel hoses with new ethanol friendly hoses

also yes you can fill it with water BUT water is "thicker" than gas and MAY not leak through a pinhole that gas would leak from.

 

[Scott Danforth]

Re: Newbie needs fuel tank help!!

we test fuel tanks at one of my old jobs with a low pressure regulator and put 2psi on the tank, then spray with soapy water. any pin holes would show up.

you are dealing with a 30 year old fuel system. I would replace all the hoses and filters.

 

[Home Cookin']

Re: Newbie needs fuel tank help!!

FTR my bulb gets firm but not rock hard. All of my boats. They start just fine. I mentioned it b/c some people new to boating pump away waiting for rock hard, and it doesn't always happen that way. The boats where they get the hardest is the short straight line from portable tank to motor.

 

[gdavies07]

Re: Newbie needs fuel tank help!!

I will find a way to pressure test it as you mentioned Scott. And where I'm this far into it i will replace all the hoses with Ethanol friendly hoses. And replace the sending unit if it checks out. 2 Questions. Alot of paint was stuck to the foam when I removed the tank. What can I repaint this with? And what is that jelly substance? (It was where the fill tube connected to the tank.) Only way I can describe it was like a jellyfish on it. Soft and slimy and translucent.

 

[smokeonthewater]

Re: Newbie needs fuel tank help!!

the technical term for the "jelly substance" is CTNCU * .... don't worry about painting the tank.... If you REALLY want to then get some etching primer and whatever paint you want.... no real reason to paint it tho.






*crud that needs cleaned up (nothing important)

 

[Scott Danforth]

Re: Newbie needs fuel tank help!!

I will find a way to pressure test it as you mentioned Scott. And where I'm this far into it i will replace all the hoses with Ethanol friendly hoses. And replace the sending unit if it checks out. 2 Questions. Alot of paint was stuck to the foam when I removed the tank. What can I repaint this with? And what is that jelly substance? (It was where the fill tube connected to the tank.) Only way I can describe it was like a jellyfish on it. Soft and slimy and translucent.

where is the "jelly substance" if it is in the tank, it is broken down ethanol, especially if it has a slight green tint to it.

 

[gdavies07]

Re: Newbie needs fuel tank help!!

It was all over the fill hose and vent tube. I must have had a leak there. Also found a mess of gas saturated foam at the opposite end. Fill/vent & sending unit are at opposite ends on this tank. I'm sure I had a leak somewhere. There was quite a bit of paint bubbling that lead to major pitting in the aluminum once the paint was scraped off. Looks like I'm in for a tank replacement. Now comes the decision of poly or aluminum. I cant seem to find a 40 gal poly that will fit. I can have RDS make me another tank but if water gets trapped in there again I'll be doing this again.. Dropping in a poly tank and foaming the sides seems like an easy way to go if I can find one that fits the hole. I can find a 30 but if smokes right which I'm sure he is, that won't give me too much time to chase the fish. I'm going to call Inca Products tomorrow to see if they have a tank that's close in dimensions or if they can make one. We'll see. Any input on poly tanks? How much do they expand when under a deck? I know my 5 gal can swells like a hot air balloon when it gets sun.

 

[smokeonthewater]

Re: Newbie needs fuel tank help!!

don't foam in a poly tank.... just strap it down... A tank only swells if it isn't vented... a permanent tank will always be vented

yep, if abused, the aluminum tank will likely fail again.... in another 30 years.... Are you still gonna care about this fuel tank around about the year 2040?

 

[smokeonthewater]

Re: Newbie needs fuel tank help!!

btw my 20' wellcraft v-20 fisherman has a 60 gallon tank... the guys on the v-20 forum that fish offshore often want more fuel than that... a LOT depends on what you're doing... 1/4 mile to an inland fishing hole 2 or 3 times in a day is WAY different than 20 miles offshore.

 

[gdavies07]

Re: Newbie needs fuel tank help!!

I'm most likely going to end up with aluminum due to not finding a poly tank larger than 25 gals that fits in the hole. But just because I'm curious... Foaming aluminum tanks is now frowned upon due to the foam retaining water and causing corrosion of the aluminum from what I understand. Wouldn't foam really lock in a poly tank? Why would you not want to foam it in?

 

[smokeonthewater]

Re: Newbie needs fuel tank help!!

because it is designed to flex when filled