rusty Puch gas tank

I have a 1977 Puch newport. It came with nasty 20 year old expired 2-stroke gas in it that had been sitting since probally 1977. Ive been working real hard on flushing the gas tank but I just cant seem to get anywhere. Ive used methods like soaking the tank in vinegar, but recently ive been flushing the tank through with paint thinner, blowing compressed air through it and sucking things out with a vacuum cleaner. And after all of that work im still getting nowhere. Im hesitant to use harder solutions because the moped has 400 on the spedo, and a beautiful apple finish on it, which I would not want to ruin at all. But after 15+ flushes theres still bits and peices of rusty compound. Need some insight on how to do this without ruining my carb and fuel filter.

Re: rusty Puch gas tank

Vinegar can require several days of soaking. DO NOT SOAK CARB OR PETCOCK IN VINEGAR

Vinegar is mild enough that it won't hurt paint so long as its rinsed or wiped off fairly quickly.

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(edited)

Re: rusty Puch gas tank

Moped Lar (OFMC) /

Vinegar for several days is all I’ve ever done for some of the nastiest tanks you’ve ever seen.

Re: rusty Puch gas tank

Jonathan Bennett /

Dish soap, cordless drill and a length of 3/8” galvanized steel cable.

I find it best to solder a couple places to prevent unraveling.

For the drill chuck end, brush about 3” with flux and solder like you’re soldering a copper pipe. For the cleaning end, come up the cable about 6” and brush a couple inches with flux and solder.

Once cooled, fray the cleaning end out. and start working it into the bottom of the tank with some soap and water. Drain, rinse, repeat. I use a pair of leather welding glove because a wire through hand would suck.

If it’s still giving you rust specs, get a steel wool, the coarse wire type, not the fine stuff. Cut a chunk of it and thread it onto the frayed end. Keep drilling. Forward and reverse. Pulling the cable almost all the way in and out but be careful because it’ll want to coil up on you.

It’s easier if you’ve got a bicycle stand so you can tilt the bike forward. I removed the front tire so I could tip it all the way forward.

I then tip it forward and get a 1/2” or 3/4” hose and use it with a shop vac to suck out as much as possible. I flush it with water and even the blow nozzle on an air compressor in the petcock hole.

Then, after I’ve gotten it as clean as possible, I go through the recommended evaporust soaking and such.

FYI, I spent 5 hours on my last Maxi. I’ve promised myself to not buy rusty tanks if at all possible.

Good luck.

And don’t forget to run a fuel filter.

Re: rusty Puch gas tank

> Jonathan Bennett Wrote:

> -------------------------------------------------------

> Dish soap, cordless drill and a length of 3/8” galvanized steel cable.

>

> I find it best to solder a couple places to prevent unraveling.

>

> For the drill chuck end, brush about 3” with flux and solder like you’re

> soldering a copper pipe. For the cleaning end, come up the cable about

> 6” and brush a couple inches with flux and solder.

>

> Once cooled, fray the cleaning end out. and start working it into the

> bottom of the tank with some soap and water. Drain, rinse, repeat. I use

> a pair of leather welding glove because a wire through hand would suck.

>

> If it’s still giving you rust specs, get a steel wool, the coarse wire

> type, not the fine stuff. Cut a chunk of it and thread it onto the

> frayed end. Keep drilling. Forward and reverse. Pulling the cable

> almost all the way in and out but be careful because it’ll want to coil

> up on you.

>

> It’s easier if you’ve got a bicycle stand so you can tilt the bike

> forward. I removed the front tire so I could tip it all the way forward.

>

> I then tip it forward and get a 1/2” or 3/4” hose and use it with a shop

> vac to suck out as much as possible. I flush it with water and even the

> blow nozzle on an air compressor in the petcock hole.

>

> Then, after I’ve gotten it as clean as possible, I go through the

> recommended evaporust soaking and such.

>

> FYI, I spent 5 hours on my last Maxi. I’ve promised myself to not buy

> rusty tanks if at all possible.

>

> Good luck.

>

> And don’t forget to run a fuel filter.

Wow, talk about doing things the hard way. But whatever works for you.

Re: rusty Puch gas tank

> Seth B Wrote:

> -------------------------------------------------------

> > Jonathan Bennett Wrote:

>

> > -------------------------------------------------------

>

> > Dish soap, cordless drill and a length of 3/8” galvanized steel cable.

>

> >

>

> > I find it best to solder a couple places to prevent unraveling.

>

> >

>

> > For the drill chuck end, brush about 3” with flux and solder like

> you’re

>

> > soldering a copper pipe. For the cleaning end, come up the cable about

>

> > 6” and brush a couple inches with flux and solder.

>

> >

>

> > Once cooled, fray the cleaning end out. and start working it into the

>

> > bottom of the tank with some soap and water. Drain, rinse, repeat. I

> use

>

> > a pair of leather welding glove because a wire through hand would

> suck.

>

> >

>

> > If it’s still giving you rust specs, get a steel wool, the coarse wire

>

> > type, not the fine stuff. Cut a chunk of it and thread it onto the

>

> > frayed end. Keep drilling. Forward and reverse. Pulling the cable

>

> > almost all the way in and out but be careful because it’ll want to

> coil

>

> > up on you.

>

> >

>

> > It’s easier if you’ve got a bicycle stand so you can tilt the bike

>

> > forward. I removed the front tire so I could tip it all the way

> forward.

>

> >

>

> > I then tip it forward and get a 1/2” or 3/4” hose and use it with a

> shop

>

> > vac to suck out as much as possible. I flush it with water and even

> the

>

> > blow nozzle on an air compressor in the petcock hole.

>

> >

>

> > Then, after I’ve gotten it as clean as possible, I go through the

>

> > recommended evaporust soaking and such.

>

> >

>

> > FYI, I spent 5 hours on my last Maxi. I’ve promised myself to not buy

>

> > rusty tanks if at all possible.

>

> >

>

> > Good luck.

>

> >

>

> > And don’t forget to run a fuel filter.

>

> Wow, talk about doing things the hard way. But whatever works for you.

+1^

Let the vinegar do the work.

I've let em soak for over a week before.

Dump, inspect and refill if necessary. When dumping vinegar out of tank drain back into original bottle in case you need to soak longer.

Re: rusty Puch gas tank

Barry (Bob) Brown /

my tank was super rusty too, I soaked it Rust Medic ($25 from Home Depot) for 4 days and picked up a flexible drain brush about 25 inches long and ran it up and down the tank throughout that time and it looks like new now.

Re: rusty Puch gas tank

Jonathan Bennett /

Mine were nearly solid gunk up to the petcock hole. I soaked and rinsed and resoaked about three times before I broke out the cable.

Not sure how else I was going to get 40 years of sedimentary rock/sludge/gunk out of the bottom of the tank.

Re: rusty Puch gas tank

> Jonathan Bennett Wrote:

> -------------------------------------------------------

> Mine were nearly solid gunk up to the petcock hole. I soaked and rinsed

> and resoaked about three times before I broke out the cable.

>

> Not sure how else I was going to get 40 years of sedimentary

> rock/sludge/gunk out of the bottom of the tank.

So was the magnum I did. It was over a week soaking in vinegar as everything in tank was solidified and the kids riding it were running fuel to motor from gas can on rear rack. How long did you soak before brushing? I never brushed. I did use ice cubes toward the end when rinsing out and shaking.

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