Fuel Tank

[snclangen]

I am going to guess that the fuel is bad....guess just looking for confirmation and pointer for easiest way to do it....

Just bought a 1978 Catalina 27 that has been sitting for at least a year....been cleaning her out and now finally getting around to engine/fuel stuff. Replaced battery and it does turn over....but the fuel tank is completely full, or so the gauge says.

Is it safe to assume the fuel would need to be drained out and if so whats the easiest way to do it without removing the tank? Oh and BTW she is in the water....

Thanks!!!

[JOHN COOKSON]

You can run off an auxiliary tank with fresh fuel to get the engine started.
You won't be able to "drain" the tank. Fuel tanks on boats have the fill and the outlet on the top of the tank.
If the fuel that is in the tank has water or KRAP in it and you have an electronic fuel pump you can pump it out with the fuel pump.

TRUE GRIT

Edit: You can check the gauge reading by rapping on the side of the tank with your fist.
Edit #2: You can get an idea of what is going on in the tank by catching some fuel in a clear glass jar and holding it to the light. If the fuel has water or KRAP in it then some of the same garbage is in the carb. You might need a carb rebuild to freshen the carb up. Do you have the Moyer manual yet? If not would recommend you purchase a copy.

[Al Schober]

sn,
You can't use the fuel pump to empty the tank either - this is because the fuel pickup tube doesn't go to the bottom of the tank. The botttom inch (or so) of the tank is a 'settling space' for water & crud. It lies there quite inertly until it gets high enough to get sucked into the pickup tube, or until an 'agitated' sea state mixes things up.
On my Tartan 30, I go in through the fuel fill with a long tube (pex or copper) connected to a Jabsco hand pump. This tube goes to the bottom of the tank. I like to check mine once a year - cheap insurance. If I find a lot of water, first thing I check is the o-ring on the fuel fill.
Recommend pumping a gallon into a clear glass jug (empty white wine?) and having a look at what you pump out. You'll probably see two phases - lower phase being water/crud and the top phase being gas.
If you only see one phase, see if it burns. If it does, it's gas and things are good. If it doesn't burn, keep pumping.
The water phase I discard, while I put the gas phase back into the tank. Yes, it no long has the alcohol content (probably good) and also has reduced octane (due to loss of alcohol) - but the A4 doesn't need much octane to be happy. Anyway, putting it back in the tank avoids disposal problems and I haven't had any issues doing this. Others on this forum have different opinions.

[sastanley]

It seems slow at first, but it really only takes about 30 minutes to drain a typical boat tank using Al's process..coming in thru the fuel fill at the top of the tank. Those orange $10 hand pumps at Wal-mart or the local auto parts place usually move about 1 gallon per minute. You just need some jerry cans to transfer into. Once you get the tank empty enough that you can remove it, I would recommend you do so and get it off the boat for total check out.
Usually the biggest issue with those $10 pumps is that the hoses are so wrapped up in packaging for so long they won't go straight to the bottom of the tank. A plastic tube (a PVC pipe that has the ID bigger than the flexible tube's OD) helps to get as much out as you can. I've even duct taped a pesky kinked hose to a fiberglass batten, and the adhesive on the duct tape was failing from the petrol, but held up long enough to remove the fuel from the tank.

[zellerj]

I agree that a tank that is almost 50 years old should come out for inspection.

My story: One spring I returned to my boat for re-commissioning and was surprised that it would not start. Turns out my full-in-the-fall-tank was empty in the spring. Some corrosion at the bottom forward edges sprung a slow leak and the gas slowly dripped out and evaporated over time. My Catalina 30 had an aluminum tank that was 40 years old at the time. I had a new aluminum bottom welded to the existing tank, which cost about $100 at a local fabricator, and reinstalled it using the same brackets.

Another time I drained the gas tank by taking off the sending unit on top of the tank and used a oil changer to suck all of the gas out of the tank and into 5 gallon gas cans, which I collected from friends. Only took about 30 minutes, just as Shawn said. Pretty easy to do. I did this to make sure that there was not a layer of crap at the bottom of the tank, just waiting to get stirred up on a bumpy sail.

My tank was easy to remove in a Catalina 30, and yours probably is too. Worth the effort and piece of mind that your tank is clean and structurally sound.

[Oldlaxer1]

sn,
You can't use the fuel pump to empty the tank either - this is because the fuel pickup tube doesn't go to the bottom of the tank. The botttom inch (or so) of the tank is a 'settling space' for water & crud. It lies there quite inertly until it gets high enough to get sucked into the pickup tube, or until an 'agitated' sea state mixes things up.
On my Tartan 30, I go in through the fuel fill with a long tube (pex or copper) connected to a Jabsco hand pump. This tube goes to the bottom of the tank. I like to check mine once a year - cheap insurance. If I find a lot of water, first thing I check is the o-ring on the fuel fill.
Recommend pumping a gallon into a clear glass jug (empty white wine?) and having a look at what you pump out. You'll probably see two phases - lower phase being water/crud and the top phase being gas.
If you only see one phase, see if it burns. If it does, it's gas and things are good. If it doesn't burn, keep pumping.
The water phase I discard, while I put the gas phase back into the tank. Yes, it no long has the alcohol content (probably good) and also has reduced octane (due to loss of alcohol) - but the A4 doesn't need much octane to be happy. Anyway, putting it back in the tank avoids disposal problems and I haven't had any issues doing this. Others on this forum have different opinions.

Al, is yours the starboard or aft galley T-30? I have aft galley and am planning on checking the lower reaches of the fuel tank this spring. Just wondering how hard it was snaking the pex down the fuel fill hose.

[sastanley]

Jim, good idea on the oil changer..those have stiffer hoses and usually a piece of wire to further stiffen the hose. You pump those bad boys up and have a beer while you watch the magic happen!

[rkohl44]

If I find a lot of water, first thing I check is the o-ring on the fuel fill.
Recommend pumping a gallon into a clear glass jug (empty white wine?) and having a look at what you pump out.

Where were you, Al, in Oct 2016???

Took me a couple months to figure this one out. Crusty o-rings don’t keep much rain out out of the gas tank.

[sastanley]

rkohl, I found out this the hard way too.