Tips for cleaning a 520H fuel tank?

[Hughes Small Engine 4]

Hey there, started running new fuel lines on my new 520H project. Got to the tank petcock and the grommet pretty much disintegrated when I touched it. I thought the tank was empty but there was a little liquid varnish left. Drained that out and got my flashlight down in the tank and found about 1/8" of the bottom of the tank is that dark sticky varnish $h!t. Any tricks for a solution to clean all that out of there? I wanted to try to avoid removing the tank since there's a snow cab on it and I'd have to pull all that off to get the fenders off. My sending unit it seized about half way up too but I can live with no gas gauge for now. Kinda just wanna get it going so I can snow blow this winter and then once I take the cab off this summer I'll replace the sending unit. Any suggestions? 

Edited December 7, 2019 by Hughes Small Engine

[pacer 3,177]

Only thing I have found is Acetone/Lacquer thinner. Pour few ounces in with 2-3-4 nuts/bolts/rocks/etc to shake around and give it a all good shake, wait 1/2-1 hour and repeat doing this til it looks clean - can sometimes take time and might have to add another batch if gets too yucky. Even then I often times have to rig up a stick/rod with a rag wrapped around the end and putting it into the tanks 'goop' and scrub it as best can. That tar like stuff can get quite stubborn

[JoeM 8,444]

The nut and bolt thing that @pacer mentioned works pretty good but you not wanting to take the tank off makes it more of an issue. I have had some success with spraying carb cleaner in the tank. Might get you by. 

[Lee1977 7,232]

I have used Oxi Clean and  hot water to clean gas tanks. Takes a lot of rinceing to get all te soap out.

Edited December 8, 2019 by Lee1977

[The Tuul Crib 7,339]

The nuts and bolts thing is good but l have 

also used diesel fuel. No way around it the tank should come off. Isnt too dificult.

 

to 

[lynnmor 7,858]

Pull the seat, fender and tank, the crud under there will be wet all winter rusting every thing.  It's only a few bolts to remove the top and the rear of the cab.  The worst part of the job is that miserable bolt above the trans filter, it is much easier to remove the filter.  Don't forget to post a photo of the crud.

[ZXT 2,401]

I'll join the bandwagon and say pull the tank. Use a chain or a bunch of nuts and shake them around inside the tank with dish soap/water inside with it for a while and it should come out pretty clean. There is no way that you're going to get it even 50% clean leaving the tank on the tractor.

After you get it clean, if you can, run ethanol free fuel only if you have access to it. That'll keep the tank and the rest of the fuel system clean. 

Edited December 8, 2019 by ZXT

[Hughes Small Engine 4]

10 hours ago, ZXT said:

I'll join the bandwagon and say pull the tank. Use a chain or a bunch of nuts and shake them around inside the tank with dish soap/water inside with it for a while and it should come out pretty clean. There is no way that you're going to get it even 50% clean leaving the tank on the tractor.

After you get it clean, if you can, run ethanol free fuel only if you have access to it. That'll keep the tank and the rest of the fuel system clean. 

I have access to it but it's crazy expensive. I run Star-Tron in all my gas which seems to work pretty good. Like a mix of Sta-bil and Seafoam

[oliver2-44 10,782]

Pulling the tank is the best option.  But if you want to try in place, I'd use lacquer thinner or carb cleaner and a pressure washer or take it to the car wash.  Start by plugging up the drain and soaking it with lacquer thinner or carb cleaner and let it set a good while to soften the goo. Then with the grommet out (bigger drain hole) angle the pressure washer wand ever direction inside you can.  ,   Let hot water build up in it so the pressure washer causes it to agitate, let it drain do it again and again again.   If needed follow this up with another soaking of lacquer thinner/carb cleaner.  

[lynnmor 7,858]

If the sending unit is still good, but just gummed up, a pressure washer just might destroy it. 

 

Go to this page to see the mess that might be there after just a few weeks of running during Fall cleanup.

 

I find it is too much trouble to keep fresh ethanol gas on hand and have been using the ethanol laced stuff without issue.  I use Stabil for long term storage, but nothing else.  If a carburetor is allowed to hold fuel for a very long period of time, expect problems no matter what snake oil is added.  I bought exactly one can of Seafoam in my life and saw no real improvement, but I had to see if this magical liquid was of any use.

[Hughes Small Engine 4]

26 minutes ago, lynnmor said:

If the sending unit is still good, but just gummed up, a pressure washer just might destroy it. 

 

Go to this page to see the mess that might be there after just a few weeks of running during Fall cleanup.

 

I find it is too much trouble to keep fresh ethanol gas on hand and have been using the ethanol laced stuff without issue.  I use Stabil for long term storage, but nothing else.  If a carburetor is allowed to hold fuel for a very long period of time, expect problems no matter what snake oil is added.  I bought exactly one can of Seafoam in my life and saw no real improvement, but I had to see if this magical liquid was of any use.

I don't use Seafoam as a stabilizer, but it works wonders on cleaning carbs and carbon build up. If I have a machine that runs pretty well but has a little surge the Seafoam 9/10 times will bring it out of it. I run a can through my bike every spring and it works wonders. Works great for cleaning carbon off of valves on direct injection car engines too. We use it at work all the time for that stuff.