This is weird... ever heard of this?

[tonynoriega]

So, as some of you know, I restored my old Evinrude 50's ear pressure fuel tank. Paint, replaced parts, etc..etc...

Put a nice decal on.
Noticed a small air bubble in the center of the decal about the size of a dime. Popped it with a needle, gently mind you, and let the air out.
Pressed the decal back in place.

Took the kids out on the maiden voyage...everything ran great.

The other night, I take a look at my tank, and the bubble is about the size of a baseball in diameter!!!!
About a quarter full of fluid.

Crap.

Sliced the bottom of the bubble open, and the fluid that drained out was fuel.

Do I have some sort of pin hole in my tank?
Smack dab in the center of the wall?

My worst nightmare just came true.

Any insight would be greatly appreciated.

 

[SumDumGuy]

bummer....

sounds like there's a hole.

 

[Johnny]

are you talking about the standard metal 6 gallon tank ??

if you can pressurize it to the max and pour soapy water over it,
you might find out where it is coming from. (and maybe others)
like the car inner tube trick.
but this definitely sounds like a very very small pin hole.

 

[tonynoriega]

Yes. This one.

Another thing I noticed, and you can tell me if this is normal or not.

When left in the sun, the tank pressurizes and swells a bit. Then when I release the cap pshhhhhhhhhhhhhhhhhhhh and the walls flex back into place "blunk"...

Normal?

Barefoot_Johnny » 6 minutes ago[/url]"]are you talking about the standard metal 6 gallon tank ??

if you can pressurize it to the max and pour soapy water over it,
you might find out where it is coming from. (and maybe others)
like the car inner tube trick.
but this definitely sounds like a very very small pin hole.

 

[Johnny]

gasoline, in its liquid state, has little expansion and contraction properties
related to the outside ambient temperatures...........
now, with that being understood, GAS VAPOR, on the other hand
will expand to the point of rupturing a plastic container. You have probably seen
this in the standard plastic 5 gallon gas cans with it half full and cap on tight when left
in a hot car or out in the sun.

here is what is puzzling - - - if your can has a small pin hole under the decal,
there should have been a pressure bleed off through that hole that would have
prevented the pressure build up and the psshhhhhhhhh when the cap is loosened.
the pin hole could be so small, that any small amount of trash could plug it. (temporarily)
If you still get the fuel leak from very small pin holes, and you want to keep the
gas tank because it is definitely cool ...... you may want to treat the inside with the
fuel tank sealer.

I presently am working on the same tank that looks like Swiss Cheese on the bottom
from sitting so many years with water in it. The sides are in great shape,
just the bottom needs work.
but now, after hearing of your experience .... I will make SURE the interior sealer reaches
every nick and cranny on the inside before put into service.




There is nothing more grand
than to be just simply messing
around in and old boat. POGO - 1960

 

[tonynoriega]

Well I found the hole... took of the deal. Which sucked and kind of made me tear up.

Worked some Acetone over the area because I had to remove the sticky glue that was left over from the decal, which was there because of the fuel getting on it... that sucked too.

But after a few swipes I could start to see where the hole was appearing.

However the hole on the outside was about the side of a pin head.

There may have been some corrosion on it when I started, and I could have potentially wire wheel brushed it a bit too hard and may pushed a piece of the wire into it somehow?

In any case, I think I am going to sand it down by hand around the area... wipe it with some acetone, and try a smooth layer of some JB Weld which I have left over from some work I did on the transom rivet holes.

Another coat of Rusto Red and call it a day.

 

[onthewater102]

JB weld would be my solution - I've got a 55 Johnson 5.5 with the same original tank - the tanks are aluminum, so it wouldn't have taken much with wire wheel to have gone too far. Feathering the JB weld over a half-dollar area around the pin hole like you would mud on drywall might be a smart move in case you accidentally wore away the sidewall elsewhere.

Pressurizing in the sun is normal, both my '55 can and the brand new plastic do it...though the aluminum can doesn't deform as a result of it.

 

[Johnny]

yea, just like drywall - - -

dimple the hole area with a ball peen hammer - rough up with very coarse sandpaper to give it tooth.
that will give you more surface area over the hole to sand smooth.

might be a good idea to let it cure a few days then fill 3/4 with gas and put it in the sun
to see if it is indeed a good patch before repainting and another new decal.

AWESOME job on the restore !!!!

 

[acabtp]

convert to a diaphragm pump and get rid of the gas sprayer/bomb

 

[onthewater102]

acabtp » 18 Jun 2014, 10:38[/url]"]convert to a diaphragm pump and get rid of the gas sprayer/bomb

DON'T! Yeah - it's safer, but your motor is 60 yrs old and still in original shape...just don't smoke near it [-X

 

[tonynoriega]

So I need to empty the gas in it to work on it?

Was hoping I didnt really have to do that, but I guess it would be smart.

 

[Johnny]

oh yea.... especially in your case, where the hole is on the side.
when you lay the can on the side to work on it, ANY gas vapor will expand
and ruin your patch job .... the can must be without internal pressure the entire curing process.

I don't think it is necessary to clean the inside for this small patch job.
just leave the cap off so it can breathe.

 

[onthewater102]

tonynoriega » 18 Jun 2014, 13:12[/url]"]So I need to empty the gas in it to work on it?...

This was a joke right? If not you might want to look up "Darwin Award" because I think you'll be in line to win one one-day!

 

[acabtp]

onthewater102 » Today, 14:31[/url]"]This was a joke right? If not you might want to look up "Darwin Award" because I think you'll be in line to win one one-day!

he's trying his hardest!

 

[He Reigns]

[attachment=-1]uploadfromtaptalk1403121746932.jpg[/attachment]

 

[onthewater102]

See that guy...don't be that guy.

 

[tonynoriega]

Well, I poured most of the gas out... couldnt quite get all of it , but close enough.

Mixed up some JB weld, used some of my kids little craft sticks and put a couple globs on the hole, and a spot where it looked like it could have become a hole down the roade.

Spread it on a bit, am going to see if I cant sand it down, then hit it with the rusto again.

Not too concerned about the look if it doesnt come out flush...

Going to order a new decal and put it on the other side anyway.

This will be the "back" side, since it is the side where the fuel and air lines connect anyway... turn that side towards the motor.

Should be good to go. Ill give a report this sunday after I take the boat out.

 

[onthewater102]

JB weld is great stuff - so long as the area was clean you should get a good bond and it'll last a **** long time.