UnVarnish Fuel Tank

[WoodTick007]

I picked up an old Mac thats like brand new. The first problem I must deal with is to dissolve or remove the varnish/gunk from the fuel tank. What is the best method or product to use to remove this gummed up, crusty old fuel?

Thanks for your help!

Greg

 

[Justin Garrison]

Does the tank split in two or is it one piece? I was faced with the same problem wih my 031. I just split the tank and scraped it out. Parts wash, brake clean, rag, putty knife, screwdriver.

 

[scottr]

Varnish removal

Greg , I've been using Mercury Marine's concentrated fuel system cleaner for many years and it works great . It is mixed 1 ounce to 4 gallons of gas . I've seen other fuel system cleaners for sale but have not tried them . Scott

 

[Lawn Masters]

I just use a little fresh gas, it works for me. the varnish dissolves in the tank, and is burned with the fresh gas. which there is a lot more of.

 

[JimR]

I just dug my old Pro Mac 650 out of storage after almost 20 years of being unused. The bottom of the tank was all varnished up. All I did was to fill the tank 1/4 full with gas and shake it up. I repeated that again and the tank was spotless.

 

[Justin Garrison]

My tank was unimaginably bad. Hopefully yours is not that bad.

 

[WoodTick007]

Well this is a crusty mess. I don't think adding fuel will dissolve it.

 

[lucky]

Not sure, but what about acetone or mek? Could make some sick fumes though

 

[Crofter]

I have seen it look like soft rubber and really stuck on. And Stinkkkkk! I don't think I would like burning it in the saw even if it would dissolve.

 

[asharrow]

This will absolutely work--without fail! Get the water-soluable paint remover. Just dump some in the tank and slosh it around. Leave overnight and rinse it out with hot water. That's it!

When I bought my 1947 Ford 2-ton, the tank had a full half inch of tarry varnish in the bottom under 10 gallons of rotten gas. I dumped the gas (which burned fine in my '48 John Deere) and put in a pint of that paint remover. Sloshed it around and let is set over night. Next day I hosed it out at a car wash. Clean as new! I have since used the stuff on small engine carbs with equally good results.

Try it. You'll like it!

Jim in Maine

 

[WoodTick007]

Jim,

Do you remember the brand you used? I only am asking because the quality of products vary so much from brand to brand. One companys H2O paint stripper can be total junk and anothers just incredible..

Thanks

Greg

 

[Al Smith]

I think I used lacquer thinner.I've had oil tanks that looked like creosote.Used WD-40 on them[ I buy it by the gallon]Most of the time,the gas lines are shot,and need replaced.When they are that bad,rebuild the carb,before you proceed,it's going to need it anyway.Why prolong the frustration?Another thing,spray some Wd-40,or LPS in the cylinder,and let it set for a while,unstick those rings.Won't hurt a thing.

 

[asharrow]

I went out to the garage to see if I had any left. No luck. I was probably looking for Zip-strip when I bought it. I remember the store said they only carried water-based and I was skeptical, but had nothing to lose but the small price of the stuff. This was probably 6 or 7 years ago, so the brand name escapes me. It was in a metal can like paint thinner comes in.

Jim

 

[Justin Garrison]

My tank was a crusty mess so I just scraped it. If there is another better way than go for it. My lines were totally shot and I put a new carb kit in it.

 

[klickitatsacket]

I like to use break clean. It does really nice job. I use 1-2 cans a week. I got a saw in that some one had been using old crank case oil for bar oil and had it totally baked all over the cylinder. The only thing I could even get to touch it was break clean. The good kind not the clorine free crap.

 

[jimbo1490]

I like to use break clean. It does really nice job. I use 1-2 cans a week. I got a saw in that some one had been using old crank case oil for bar oil and had it totally baked all over the cylinder. The only thing I could even get to touch it was break clean. The good kind not the clorine free crap.

This is IMHO the best suggestion in this this thread. MEK, acetone, lacquer thinner, paint remover will all remve/dissolve fuel varnish OK, but will likely strip off all the paint. This is not good. "Brakleen", the real stuff in the red and black can from CRC industries will remove the varnish and NOT the paint. Beware that cheaper generic 'brake parts cleaner' advertized as 'chlorine free' is just dumb old lacquer thinner, a blend of ketones (acetone, MEK) aromatics (toluene, xylene) and alcohol. This will definitely eat the paint off of your saw.

What's more many paint removers are definitely off limits for magnesium. Some eat mag mercilessly! You have to be careful! In my working life I am an aircraft painter. I KNOW about stripping and painting MAG and have ruined my fair share by using the wrong paint remover on it. You would be suprised how quick it eats it. Even if you get it off quick enough, it then sets up very aggressive corrosion thereafter unless you beadblast the part afterward.

If you have a tough time finding the CRC Brakleen product, the special cleaner for Paslode nail guns sold at Home Depot is basically the same stuff.



Jimbo

 

[oldwild]

What about removing scale or corrosion inside of a tank that looks like it sat for a long time (tank off my 1130G). Look like scale type of deposit, not varnish. Does not remove very easily from the tank, and is Magnesium! Tried splitting the tank and it will not come apart!

 

[Sparky_NY]

I have seen every thing suggested but what I would think would be the obvious, carb cleaner. When rebuilding a carb it is commonly used to soak the components in to cut deposits and varnish, including in the passages. It is made and intended for removing these types of deposits.
The only warning with carb cleaner is to not use it on plastic or rubber parts, so removing the tanks line and filer would be a good idea.
Get the gallon can type of carb cleaner, not the spray cans. I rebuilt the carb on my motorhome last summer and got a gallon at AutoZone for about $15. It is a pretty serious solvent, even removes paint, but made for the purpose.

 

[Crofter]

Oldwild;
The corrosion on the magnesium might be better left alone. I dont think it will dissolve with the fuel and taken in to the saw. Any loose stuff that does fall off will be stopped by the pickup filter. You might try using Acetic Acid (vinegar) with caution. While it wont touch aluminum at all it is quite active on magnesium, though it might not touch the corrosion either. Just something to try.

 

[oldwild]

After many many hours so far in sealing and working on the holes in the tank top, I think I will just wash the tank out, and leave it alone. I haven't been able to find a tank top let alone a whole tank! Don't need to destroy it!