B.O.A.T (bring out another thousand) Leaking fuel tank

[thegoat86]

Just literally got my motor out, engine coupler changed, motor and drive back in, and all the interior back in.

Cleaned everything up and washed the boat for a run on the bay this weekend.

Came home from work yesterday with the strong smell of fuel in my driveway. I went to the back of the boat and noticed a trickle of fuel coming out of the drain. Got some buckets and started looking for the issue. Maybe a hose or something forgotten..... Nope, Its coming from under the tank. Nice. Now I need to take the boat back apart and cut the floor open to access the tank. I will be looking for some pointers on creating a permanent hatch or access to the tank. Kinda foolish for manufacturers not to give an access. Would save everyone time and money.... Wait that's the reason they don't. LOL.

I did a quick search here for a thread showing replacement or detailed info on this process to no avail. I will be posting photos and info as well as where I sourced the new poly tank I am going to get. Stay tuned.

 

[nola mike]

That sucks. Good news is you should be able to just take up part of the floor like I did a few years back. I didn't have to reglass the stringers or tab into the sides, which saved a lot of time. Still no fun though.

 

[thegoat86]

Wondering If I could do a hatch out of starboard or similar material? May work for a more permanent solution. Only have to pull the carpet up to access it in the future.

 

[Bondo]

Wondering If I could do a hatch out of starboard or similar material? May work for a more permanent solution. Only have to pull the carpet up to access it in the future.

Ayuh,...... 1 of the barges I'm buildin' right now will need hatches, some deck areas,.... all fiberglass right now,...

The way the lay-out is comin' together,.....
I'm thinkin' diamond plate aluminum, .063", with stiffeners tacked to the underside to locate 'em,.....
.063" ain't a toe stubber like some,.... flat on flat should somewhat self-seal against water intrusion,....

This topic has Nothin' to do with Mercruiser, so I'm gonna move it,.....
It could go to the repair/ rebuild forum, or general boatin' forum,.....
I'll give You the choice,.... Which is it,..??

 

[HT32BSX115]

Now I need to take the boat back apart and cut the floor open to access the tank. I will be looking for some pointers on creating a permanent hatch or access to the tank.

Howdy,

You're kinda on your own here! I am sure you're thinking about this but PLEASE be careful cutting the floor with any kind electrical power tools (except maybe certain brushless motors etc) .

Most of them produce visible sparks and if there's enough fuel vapor and the ratio is right, you'll run the risk of igniting them and placing yourself in a "Fire Pit"

If it were me doing it, I would suction all the fuel out of the tank using a siphon hose through the gage sending unit hole. Then get a bilge blower (like the one below sold right here on iBoats) and use cheap dryer hose etc to place a slight vacuum on the tank. With the hose on the sender hole and the vent and fuel fill open, you'll suck out all the vapor and replace with fresh air through the fuel fill and vent. (DON'T USE A SHOP VAC.......BIG SPARKY MOTOR!!!)

DON'T DO THIS IN YOUR GARAGE .......DO IT OUTSIDE and I'd let it run for a day or 2 after getting all the visible liquid out of the tank. (The senders are usually at the back of the tank, so raising the bow a little ensures all the liquid is pooled at the back of the tank so you can get most of it with the siphon) AT THE OTHER END OF THE HOSE AWAY FROM THE BOAT!

After completely draining the tank of all liquid, place the dryer hose over the gage sender hole with the fan at the other end. (power it with a small 12v power supply or small battery charger)

With the fuel fill open you can let that fan run for a day or two to get it all.

Even then, after that, I would probably pump argon or other inert gas into it (using the argon tank on my Tig welder or the Argon/CO2 on a MIG) and then close off tank openings(vent, fill, gage sender)

You can also fill it with water and siphon drain it (a couple of times) and then fill it with water + some dish soap to get all the gasoline. THEN run the fan for a day or so to get all the vapor out.

Gas tanks scare me. I have seen the pictures of tanks that blew up!! It wasn't pretty!

Cheers,


Rick

 

[GA_Boater]

This topic has Nothin' to do with Mercruiser, so I'm gonna move it,.....
It could go to the repair/ rebuild forum, or general boatin' forum,.....
I'll give You the choice,.... Which is it,..??

Moved to the General section cuz at this point thegoat seems to asking for advice. He can start a Repair thread in the Repair/Rebuild section when he decides what to do.

 

[poconojoe]

Agree with Rick. Adding my 2 cents... if you have a compressor, to use air tools.

 

[thegoat86]

I got the tank out, The tank coffin did not have a drain hole. The fuel/water was full to the top in the coffin and was spilling over where the fuel filler hose went in. I hole sawed a drain for the water. I cant imagine why it would be completely sealed off other than the obvious not wanting to spill fuel into the motor area where the bilge is..... I may want to reseal it up? Or leave the drain in there? Maybe get a plumbing plug with the wing nut so it seals good? Then I can drain it if need be under controlled situation?

 

[thegoat86]

Anyone got a lead on where I can source a decent poly belly tank? I am hitting a wall. Moeller has some good ones, but they are too long for the 40 gallon range. I don't want to have to cut and relocate the coffin support.

 

[thegoat86]

Moved to the General section cuz at this point thegoat seems to asking for advice. He can start a Repair thread in the Repair/Rebuild section when he decides what to do.

I will start a repair thread once I get things sorted. Thanks GA

 

[HT32BSX115]

I had to replace the tank (Steel, 18-gal in the bow) on my previous boat. I was able to buy an aluminum 26gal tank of dimensions that would fit from West Marine. I can't remember who the manufacturer was.

If your's is rectangular, you might be able to either buy a poly or aluminum one from various makers. Or you might just have to go with a custom tank

 

[Bondo]

I cant imagine why it would be completely sealed off other than the obvious not wanting to spill fuel into the motor area where the bilge is.....

Ayuh,.... All my barges, Drain, stem to stern,.....

Try these guys,....

 

[HT32BSX115]

I got the tank out, The tank coffin did not have a drain hole. The fuel/water was full to the top in the coffin and was spilling over where the fuel filler hose went in. I hole sawed a drain for the water. I cant imagine why it would be completely sealed off other than the obvious not wanting to spill fuel into the motor area where the bilge is..... I may want to reseal it up? Or leave the drain in there? Maybe get a plumbing plug with the wing nut so it seals good? Then I can drain it if need be under controlled situation?

When I removed the 460+OMG King Kobra from my boat (in my sig) and replaced with the Mercruiser 454, I moved the bulkhead in front of the engine (at the back of the tank) forward about 3 inches which simply matched the length of the aluminum tank a little closer.....giving me more room in front of the engine for better access.....

I had a hole in the bottom of that bulkhead that would allow water to drain from where the back/bottom of the tank is into the bilge. It is 3 or 4 inches higher than the bilge and actually more than high enough where the bilge pump would start pumping long before the level in the bilge got anywhere near the drain.

And there was a drain there previously from the back of the tank area to the bilge. I would say that's common for that area to drain into the bilge.

I would'nt close it off under any circumstances.

 

[thegoat86]

I installed an ABS Moeller 38 gallon tank. I lost two gallons, but this one was a direct fit without opening up the coffin. Seems to work well. We moved inland and now the boat is going to retire on the st. johns river. The salt water use destroyed almost everything. I installed two bilge pumps, new steering, new controls, new engine coupler, new guages, yada yada....

 

[HT32BSX115]

I installed an ABS Moeller 38 gallon tank. I lost two gallons, but this one was a direct fit without opening up the coffin. Seems to work well. We moved inland and now the boat is going to retire on the st. johns river. The salt water use destroyed almost everything. I installed two bilge pumps, new steering, new controls, new engine coupler, new guages, yada yada....

WOO HOO! Good job! :thumb:

 

[Chris1956]

My SeaRay had wall-to-wall carpet. The fuel tank had a carpeted piece of plywood over the fuel tank as a hatch. It was hardly noticeable, and could be removed with 4 small stainless wood screws. The plywood hatch was reinforced with poly resin and a piece of glass, under the carpet. I would guess something like that would work for you.