Dual fuel tank not used for a while, questions
 

I am looking at buying an 87 R10 that has dual tanks. The PO told me that she only used one tank and never filled the other tank up. She wasnt sure if the dual system was working or not. My concern is that this tank hasnt been used in a long time. I am guessing i will have to replace everything to get it back working properly? tank, pump, and more than likely the switch? Any input would be great. I am sure at one point the switch quit working and instead of fixing the PO just used the one tank, but i am guessing that sitting for so long without being used ruined the rest of the system.

Re: Dual fuel tank not used for a while, questions
 

The tank will have rust scale if it's been kept empty. having fuel in it usually helps against rust.the filler lines may be rotted. but as long as you back flush the lines for the second tank they should be good. check you switch and wires for proper connections

Re: Dual fuel tank not used for a while, questions
 

How long did the PO run off of 1 tank?
My '86 ran off of 1 tank for about 4 years, (length of time PO had it.)
Switch worked, added a few gallons of gas and some Marvel Mystery Oil, ran it. Wasn't great, but cleared up.

If longer or unknown, I'd go with what Goldfinger said.

Re: Dual fuel tank not used for a while, questions
 

You can probably resurect the old tank. Keep in mind it will for sure be rusty. I would suggest putting 2 inline fuel filters right out of the tank. The the dirty gas will be filtered twice before entering your system ie pump, switch and existing filters.

My guess would be the biggest issue may be that your tank switching servo may not work. It is easy to replace and it is back by the right hand fuel tank.

So easiest method would be fill up that tank to minimize rust to gas ratio, see if tanks change, easy to see by fuel gauge, if gauge changes and fuel goes down after using it a while, the switch and servo are working. Just be sure to stuff at least one filter in right out of the tank and be prepared to change these a few times. At 4 bucks a piece its cheap insurance. Good luck.
The above is the hillbilly method and has worked fine for me in the past.

If you want to go all out you can remove the tank, remove the sending unit plate, throw a bunch of old nuts on a wire( use a wire and connect the ends this is so you can get all the nuts out after you are done), at least 18 inches worth and have you and a buddy shake the s hit out of it with some solvent in it, this will remove a lot of the rust or have it steam cleaned, usually a rad shop has the capability for this. If you do do the shake, still filter it at the tank.

Best of luck!

Re: Dual fuel tank not used for a while, questions
 

My son and i recently had the same trouble with a 73 we picked up. A mechanic said that they just take their gas tanks to a radiator shop and have them cleaned out, removing gunk and rust.

Re: Dual fuel tank not used for a while, questions
 

Thanks for all of the input guys! Very helpful!