Help me not explode.

alk

alk

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filled both 150 gallon gas tanks to the top last night, in anticipation of my 90 mile run today for winter storage. What I didn’t know until about two minutes after I got done filling, there is threaded inspection port on top of the port tank that leaks when the fuel reaches it.

I siphoned five gallons out of the tank to stop the leaking, and ran the boat today, everything looked nice and dry on arrival. Now that the tank is down near quarter full, I don’t have to worry about fuel leaking out the top - just the vapors. So I still need to fix it. Winter project number One. I guess two questions - first is what do I seal the threads with? Is there a permatex that is fuel resistant, yellow teflon tape? Something else?

I’m a little worried that the plug corroded away where it meets the threads, and is going to a be beach to get off. While I don’t recall ever seeing a spark when trying to remove a plug from anything, if it happens, ka-boom. I was thinking of coating everything with grease, to quell any sparks. Any other suggestions on how to mitigate this situation? Thanks!
 
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Wait, you had a gas leak and your fume detector didn’t go off??? Replace it!!!

I don’t really see how removing the plug could cause a spark as long as you use the right socket or box wrench.

If it’s really jammed or corroded and doesn’t come off, I would just seal the gap with thickened epoxy and be done with it
 
Funny you mention - there is a fume detector in the engine room, I doubt it works, but none in the aft cabin - under the bunk is where the tanks are. There is a second halon system down with the tanks ( which probably doesn’t work). Trying to figure out what good that would do if a fire broke out next to 300 gallons worth of fuel tanks.

The bottom threads are the ones leaking - I’ll need a huge socket or box wrench - didn’t have a chance to measure today, but 1.5” at least. I had a pipe wrench on it last night - didn’t go crazy with force because it would have been a disaster if it tore out. But with what I gave it, which should have been enough, it didn’t budge,
 

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A gas boat without a fume detector scares the crap out of me… I would put one in the engine bay AND in the bilge where the tanks are.

If you have room, a pipe wrench should work, maybe use duct tape to avoid any possible spark but I doubt that s a concern. Or you can just buy a socket. I had to buy one to remove the gauge sender on one of my water tanks, 2 1/2” I think, got it on Amazon it wasn’t expensive.
 
This may be a job for a professional.

George
 
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I had a similar problem right after purchase; filled up both main tanks and the port tank started leaking at the too. Fumes were awful. We shut everything off, unplugged power cord, and notified the marina that sold us the boat.

They sent a mechanic to fix it and we spent the night in a motel.

Replaced the faulty fume detectors too.
 
Bruce Herrington said:
I had a similar problem right after purchase; filled up both main tanks and the port tank started leaking at the too. Fumes were awful. We shut everything off, unplugged power cord, and notified the marina that sold us the boat.

They sent a mechanic to fix it and we spent the night in a motel.

Replaced the faulty fume detectors too.
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I slept on the aft deck Friday night, it was cold, and sort of rained. But the smell inside was unbearable. It’s better know though.

I would prefer a pro deal with this one, hate doing anything with gasoline, but unfortunately the boat yard near my house where I do winters doesn’t really have service. So I’m on my own. Going over later today, I think I have sockets up to 2 inches, and some larger metric. Can’t really get in with a wrench, has to be a socket.
Assuming it comes out, This stuff on the threads?

www.jbtools.com

Permatex Permashield Fuel Resistant Gasket Dressing and Sealant (85420)

Get durable, flexible gasket dressing with Permatex Permashield. Resistant to gasoline and automotive fluids. Order now!
www.jbtools.com www.jbtools.com
 
I'm almost certain something like this was used by the marina mechanic to repair/replace leaky part.

This was back in 2013..
 
I guess I got lucky this afternoon. While I didn’t have a 2 1/8 socket to grab the large fitting ( the one leaking) - in the four type of metal rigging that the tank fabricator assembled, the stainless steel fitting was even more corroded to the iron china adapter, and that one was only 1 1/8” - had a socket for that, and the assembly is out. On my way to do some shopping, would like to replace the entire thing - but at a minimum the threads will be sealed!
 

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I usually use pipe tape on these. No need to over tighten either. On my personal boat i remove the inop fuel gauges fittings in a companionway floor to use a calibrated dipstick. On the 116 I run, there is a plug to use a dipstick on the 3000 usg main tank as well. Pipe tape works fine never had a leak even with full tanks. Of course that’s diesel but I don’t think gas dissolves pipe tape, does it?
 
There is a permatex pipe thread sealant that works with petroleum products. I’ll see if i can find it.
 
Went to Home Depot prior to the auto parts store, wanted to simplify the assembly. While I understand the logic of putting a plug an inch or so above the tank top - going from aluminum to galvanized to stainless and back to galvanized seemed like a corrosion invitation to me. So I went with the galvanized plug shown. I hope I chose the right material - Home Depot had plastic, black iron and galvanized. Stainless is available at the plumbing supply place, I was told.

The thread sealant specifically mentions gasoline, so I should be good. Smoked a cigar on the deck after I finished, and I’m still here. So I think I’m done. Just need to decide before spring if I want to redo the other five access points on top of these tanks.
 

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May as well get them all cleaned up. If one was bad, could the others be far behind? At least take a close look at them all.
 
Just seeing this, good call on the sealant made to handle gasoline, personally, I would not trust teflon tape around petroleum gas but it does work on natural and propane gas which makes research difficult!
 
boatbum said:
May as well get them all cleaned up. If one was bad, could the others be far behind? At least take a close look at them all.
Click to expand...

That’s what I’m afraid of. But I was lucky, surprisingly the first one that went was the one with best/easiest access. Each one gets a little worse. But will be easier now than if I wait until gas is weeping rapidly out the top of the tank again!
 
WALSHIE said:
Also, have you ever used a basin wrench? They are very handy for situations like these but I'd be concerned if you would be able to get enough bite on the fitting to remove it. https://www.homedepot.com/p/Milwauk..._icJDuKD0E_GkudEIUAaAiELEALw_wcB&gclsrc=aw.ds
Click to expand...

That’s one I’ve never used / owned. Was hoping to get this project done without a tool purchase; but that never happens!

If I take the plywood top off the bunk assembly which was built around the tanks, I’ll have very good access to all of the fittings. But whoever built it used 14 million screws. Probably not going to use a cordless, as mine is a spark thrower. Perhaps I’ll lug a compressor over and an air powered driver ( which I don’t own yet).
 
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