Cleaning metal outboard tanks

Stumpalump

Chief Petty Officer
Joined
Dec 5, 2013
Messages
413
I've got a Merc tank and two OMC metal tanks from the 80's that were full of old rotten gasolene. Luckily little to no rust because of the desert. They have that brown goo from ethanol and they need a good washing of the inside. Any recomendations as far as soap goes? I'd like to use water and dish soap or laundry detergent IDK? I'm thinking the gaskets for the mechanical level sensors and fuel line connection port will get ruined so I'd prefer not to disassemble them. How would you wash them out?
 

hardwater fisherman

Lieutenant Commander
Joined
Mar 19, 2010
Messages
1,725
I had a 3 gallon metal tank that had some of the brown goo also. I just put in some straight gas and swished it around. Turned it upside down. I would say the hardest part is getting it all out of the tank after.
 

Grub54891

Vice Admiral
Joined
Jun 17, 2012
Messages
5,908
Throw some nuts and screws in the tank with whatever solution you use, it will help scrub the tank when sloshing it around. use a stick magnet to remove them when done.
 

Stumpalump

Chief Petty Officer
Joined
Dec 5, 2013
Messages
413
Throw some nuts and screws in the tank with whatever solution you use, it will help scrub the tank when sloshing it around. use a stick magnet to remove them when done.

I was wondering how tuff the level float and pickup tube are before I put anything inside. I've heard to use chain but that's too ruff.
 

82rude

Rear Admiral
Joined
May 8, 2012
Messages
4,082
Any very old gas will give you that varnish stumpalump.Poor eth gets blamed for everything:joyous:
 

Grub54891

Vice Admiral
Joined
Jun 17, 2012
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5,908
If the float is cork, or the wrong type pf plastic, some carb cleaners will destroy them. I'd go for removing them.
 

JimS123

Fleet Admiral
Joined
Jul 27, 2007
Messages
7,952
Pull the gauge/float unit off the top of the tank. When replacing the part, put on a new gasket ($1.50 part). Also, replace the cork float with a synthetic rubber float (Google the part number).

Pour the contents out and then use a full pressure garden hose to flush the tank. If there is rust, use the nuts and bolts procedure as listed above.

Pour out the contents again. Drop in a small bottle of rubbing alcohol to displace the water, and then drain again. Put it in the sun to evaporate the alcohol. Finally, drop in 1 oz of 2 cycle oil to coat the inside. Fill with gas and have a tank that will give you another 10 years.
 
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