I recently got a1989 Honda Fourtrax that wasn’t running. I went through the entire machine and eventually replaced the carb and got it running perfectly. A few days later the engine quit running due to fuel starvation. I took the carb apart and found the jets clogged. An overnight soak in carb cleaner and it was good as new.
Investigating the cause I discovered rust in the gas tank. Apparently the previous owner had let the ATV sit in his garage for two years with almost no gas in the tank. Moisture in the tank caused a build up of rust on the inside. So now when gas is poured in the tank bits of rust come off the tank, mix with the gas and cause havoc with the carb. The gas comes out a muddy brown color from the tank.
My initial thought was to install an in line gas filter, but space it’s tight and the gas is feed by gravity, not by a fuel pump so the filter impeads fuel pressure. The correct solution is to remove the rust from the tank. This I can do by using small bb like items, some water and a lot of agitation. The bb material will remove the rust but I have to find a way of sealing the freshly rust free tank, otherwise the rust will just reappear. Here is where I’m at a loss. Any ideas on how to accomplish this? Does anyone know of a product that can be applied to the inside of the tank to seal the metal? Remember, it had to be impervious to the effects of gasoline.
The easiest solution is to purchase a new gas tank, however a new one cost close to $400 and I’m not willing to spend that kind of change if I can figure or another option. They are available used on eBay, but they start at $150 and there is no guarantee that they’re any better than what I have now. Any suggestions would be appreciated.
There’s purpose-made gas tank sealants out there that aren’t too spendy. The POR-15 based ones are the most common. Honestly, though, there’s nothing wrong with a little bit of rust in the tank. Steel gas tanks are always going to have a bit of a patina to them on the inside. Most likely what clogged the jets was the residue from the old gas, not the rust.
What I’d do is just rinse the tank out. If you have a friend with a parts washer so you can rinse it with gas, that’d be ideal, but I’ve just done it with a garden hose (although make sure you dry thoroughly before re-installing if you do that!). Rinsing it out gets the big chunks and the loose stuff out which is all you really need to worry about. After that, just make sure your gas cap seal is good and that when you put it away for the season you drain the tank and carb or run it out of gas if the carb doesn’t have a drain.
Junkyard? A vehicle that’s been in a head-on collision, for example, might have a salvageable gas tank. Subsequent and/or similar models might have used the same tank.
I would not recommend any type of sealing product that are marketed for rust prevention in fuel tanks.
I have an early 80’s bike whose tank was lined with one of these products. The lining had mostly disintegrated, adding to my problems. This generally happens to any liner product.
On top of that, the unlined portions were mostly rust. To fix this, I bought a gallon of acetone from Home Depot, poured it along with a handful of stainless steel nuts into the tank (with all petcock/filler holes sealed) and shook vigorously off and on for about 3 days. After seeing mostly fresh metal, I poured the acetone/nut mixture out of the tank, let dry for about an hour, replaced all petcocks and filler cap, and filled with gasoline.
The best way to prevent rust is to keep the tank full at all times! And if you don’t intend to use the machine for a while, add a fuel stabilizer.
Yes, of course. The idea is to use a recent arrival, which you could find out through the people running the junkyard. Some are friendlier than others, but the fact is that it’s a perfectly reasonable question. If that’s not possible (jerks with no competitors nearby, for example), you can keep tabs on the stock yourself. I guess that isn’t much of a solution if you’re in a hurry.
Inquire at a radiator repair shop. For automotive gas tanks, the one I deal with typically opens (bisects) the tank, cleans it thoroughly, seals the inside surface properly, and reassembles the tank. Their advice has been that if the tank is not thoroughly cleaned and properly sealed, the problem will continue.
With the talk of “splitting” tanks to clean and finding a usable replacement in a junkyard, let’s keep in context that the OP is referring to an ATV, not an automobile.
Thanks for all the responses. I’ll look into each and eventually find a solution. Ass far as a junkyard, KAZO is right. It’s an ATV and while I’m sure they are out there I haven’t been able to locate a ATV recycler. A plastic tank would be a great solution, but I don’t think they make one. I’m going to inquiry at a radiator shop tomorrow.
Looking closely at the tank it is obvious that it was made in two parts that were welded together. I might steam the tank to remove any traces of fuel and foretaste the halves, then I can sandblast the interior and have great access to put a permanent sealant on the interior metal.
I get the problem, the rust spots that are present catalyses further rust.
There is one treatment - Phosphoric acid.
Apply it and let it soak in.Then rinse the tank out 4 times with fresh water.
Then let the tank dry before use.
It converts any rust to solid iron phosphate which is definitely not going to degrade due to the action of petrol. This should help stop flakes coming from the more rusted out sections
The iron phosphate will not be dissolved into fuel.
Also the acid will NOT do any harm to rubber or fibreglass.