Passenger fuel tank problems

[scoutingitout]

I have a very frustrating issue with the passenger side fuel tank. I lined it with Por 15 and had most of it flaked back off inside the tank. I cleaned and cleaned and rattled a chain in it, hosed it out with water let it dry completely until I can see nothing in it and it still runs a few minutes and stops delivering fuel. I put a fuel pump screen on the end of the pickup tube ( these are all things I have done to the drivers side tank and it works fine.) I have blown out the lines and even tried wrapping the exhaust with insulation tape for exhaust. I noticed the muffler got hot enough to melt the adhesive off the tape which I didn't think it would do that. My thought is the exhaust is too hot and too close to the tank fuel line and it's boiling the fuel. I don't know what else I can try.. I want to go camping/wheeling for the next few days and this is going to make it very difficult.

[lonnie]

from the pics, it appears you have located the muffler next to the fuel tank. this is not a typical location nor it is ever a good idea to locate a large heat source (the muffler) next to the tank. the muffler design you have also spreads the heat over a large area.

if you choose to stay with this muffler, i would relocate it to the rear of the rig. exhaust heat tape is not widely used for a number a reasons, i would reduce the radiant heat transfer with a shield (preferably stainless). alternatively there is high temp fuel line which you can use and while it is certainly expensive it does work very well.

[scoutingitout]

I pulled this exhaust off my parts scout. The one that was on mine was rusted away. I just drove a short distance, about a mile, and that was enough to melt the adhesive off the insulating tape. I think the muffle may be partially blocked. It gets very hot. I was planning on heading out early tomorrow as I have people waiting. I am about to cut the exhaust off right before the muffler to see if it is the problem. Never seen one get so hot so fast. Since the driver side doesn't do this I can only believe it's a heat problem. Thanks for the post Lonnie, I just can't think of what to try next and I am out of time really.

[scoutingitout]

I failed to mention I placed a piece of steel, a side cover plate from an old computer case between the fuel lines/ tank and the muffler with no change. I put insulation tape on the muffler and the piece of steel and no change. Maybe I can come up with money to run the exhaust where it was originally when I return from the mountains but since I am a lover of nature it is my first priority to get there. I know silly to put the needs of my Scout after my needs of open spaces..

[SCOUTMAN67]

I don't think the heat from the exhaust is causing your problem. A mile isn't going to do it. Also, it looks like the muffler is right under the pass. side floor, right? If so, that's an "ok" spot to put it. Not the best, but it'll work.

Does it run out of gas when it's idling, or just when you're driving it?

-Gary

[scoutingitout]

It did run out of gas while I was sitting at an intersection yesterday in the subdivision. If it's not the heat then Maybe the tank selector switch is faulty somehow. Just guessing at this point. Thanks for any advice I may receive while I'm away. I'll attempt to watch this thread while I'm gone on my phone. I'll let you know if I find a solution.

[SCOUTMAN67]

It could be the fuel tank selector. Do you run it on the dr. side tank and then switch it over to the pass. side and then it dies? Are you turning it the right way? The original ones are different than the aftermarket ones. Some are 180 degree valves and the newer ones are 90 degree valves (meaning you turn the handle 90 degrees to select tanks). But, that would be too easy

-Gary

[Albuq. Henry]

When I first got my yellow one going, I was having an intermittent fuel line blockage on my pass side tank... I think there was something in the tank that would get picked up and the fuel would stop... When it would stop on me I started disconnecting the line a piece at a time to see where the fuel stopped... It ended up being the piece inside the tank... It slowly went away... I think the rust or whatever it was slowly broke down.. I figured out that if right when it started to spudder if I would switch to the dirver side and keep going.. then I could switch back and be ok for maybe the rest of the trip or for just a couple miles... I figured that when I switched tanks and the fuel stopped flowing the piece of whatever would fall back into the tank and be ok until it got sucked up again.....

[lonnie]

it seems unlikely this could be a heat problem given it acts up so quickly. without more pics it is hard to tell. i think scoutman67 may have the explanation.

[Drew Merrick]

since you have the tank all fixed up and a screen on the intake your next place to check would be the fuel selector valve. They can get crap in them that blocks the passages. I would also replace the fuel lines leading from that tank to the fuel selector. If your pump is on the engine and you have a slight puncture or broken seal on the line to the tank then your going to have the same problems as a straw with a crack above the liquid line.

other sources of the problem. Probably not the cause but something to consider. Because the drivers side tank appears to work then that rules out the fuel pump and the gas lines from the selector switch to the carb/injector/monkey with a squirt bottle or whatever gets fuel to your intake.

Fuel boils at 100 deg F. to 400 deg F So any heat source raising the temp of your fuel down the line to > than 100 potentially can give you vapor lock. I am not about to run the calculus on the change in surface area and thermodynamic cooling properties of your fuel line the further it gets away from a heat source, but a muffler running hot right under the gas tank might be something to consider. Maybe putting an actual heat sink or heat shield between that muffler and the bottom of the tank mounted without duct tape for instance.

Is there any point along the path of the fuel line that it comes to contact with or very near the exhaust path? Again, pointing out places where the heat of the fuel may be raised to temps that cause it to boil.

[walker]

Might be a leak on the suction side of the fuel line, between the the fuel pump and the tank letting air into the line, or the 3 way valve might be plugged. Remove the line from the fuel pump and blow air backwards through it to make sure it is not plugged, then plug the fuel pick up end and pressurize with a few pounds of air and soap all the fittings. My bet is the valve, though my fuel pickup tube was plugged with dried gas varnish when I got mine.

[guidolyons]

Like the other guys have said, check the suction line in the tank, the line to the 3 way valve, and the 3-way selector valve itself . There's not much to it (the top unscrews and pull the stem out) Mine had a bunch of crud in it, and now it's started leaking around the valve. A new valve is about ~$20-25 from most marine/boating stores. Personally, I don't think it's a heat/vapor lock issue, I think you have some crud that is stuck in the line. *edit 1/4" *edit steel line is cheap, just replace it and see if that fixes it.

That being said, the muffler right under the gas tank probably isn't the best idea, either.

If it is caused by heat/vapor lock, it's time to move the exhaust or at least use/make better heat shield.

Also, that wrap you used is not made to be applied directly to the exhaust/muffler, that's why it's coming off. That style is made to wrap what you want to protect from the heat (fuel lines, etc) as a heat barrier from radiant heat, not wrap the exhaust itself.


If you want to wrap the exhaust instead of relocate it, get the header/exhaust wrap that is made for wrapping exhaust. There is no adhesive, it's secured with stainless steel zip-ties or hose clamps.

[scoutingitout]

Originally Posted by SCOUTMAN67

It could be the fuel tank selector. Do you run it on the dr. side tank and then switch it over to the pass. side and then it dies? Are you turning it the right way? The original ones are different than the aftermarket ones. Some are 180 degree valves and the newer ones are 90 degree valves (meaning you turn the handle 90 degrees to select tanks). But, that would be too easy

-Gary

I have tried switching different directions, different amount of turns ( handle pointing to drivers side, handle pointing up or down etc.) And always the same result, a few minutes and it just seems to run out of gas until I switch it back the drivers side tank

[scoutingitout]

I think I'll try taking the selector valve apart and see what I see. As for the tape I learned real fast it wasn't meant for exhaust applications.. And what a wonderful aroma it made too. I knew I should have had a new exhaust system put on it a few months ago but couldn't pass up bolting this one on and driving around. So hopefully I can get that taken care of soon and eliminate that in the list of possible causes.

[Albuq. Henry]

You can take the lines off at the selector and try to blow through them. You should get bubbles in the tank...

[scoutingitout]

Took the selector valve apart and it just ran out clear fuel, no flakes or discoloration. I had blown the lines out both directions the last time I had the tank out and they seem clear. That muffler gets so hot I can't touch it and I think it is hotter than it should be but it is a short distance from the engine. ran it over 150 miles this last weekend did some light wheeling and as long as I never used the passenger tank it ran fine. Next step I'll just replace the lines.

Thanks for all the ideas. I am trying each one as I am at a loss.

[Albuq. Henry]

My bet is there is something in the tank that is plugging the pickup tube..

[scoutingitout]

All great ideas. I have done everything mentioned except replaced the hard line from passenger tank to the selector valve. Been thinking of getting a different valve as well, there could be something in the manufacturing.. Guess I'll try cleaning the tank yet again as well. Thanks again for all your suggestions.

[scoutingitout]

Is it possible to remove the selector and run a simple two into one type of junction. Would the fuel flow from both tanks at the same time, would it not have enough vacuum to pull from both at the same time.. At least I can eliminate the selector valve that way.

[Albuq. Henry]

I dont think that would work cuz when one began to suck air you would nver get the other to pull fuel... basicly an air leak...

If you want take the selector out of the mix just bypass it with some rubber hose for a while and go to the tank you want......

[scoutingitout]

I knew it couldn't be that easy. Was an idea anyway..

[Albuq. Henry]

Actually semi trucks do that they pull from both tanks and with fuel injection there is return. there is a special valve with a spring in it that keeps them equal. Also lines to both sides have to be equal length... so you arnt that far off it can happen...

[guidolyons]

Originally Posted by scoutingitout

Is it possible to remove the selector and run a simple two into one type of junction. Would the fuel flow from both tanks at the same time, would it not have enough vacuum to pull from both at the same time.. At least I can eliminate the selector valve that way.

You could...but I wouldn't. With both tanks connected with no valve, the fuel will always try to equalize between tanks, (like a mason's water level).

[scoutingitout]

Taking out the selector valve is a desperate idea.. I didn't think it would work.

[lonnie]

well, the blockage can only be in the line, pick up tube or switch. line is cheap, just replace it. when you had the switch out ,did it have two working positions, if yes then you are only left with a tank problem. if no replace it, they are cheap. pulling the tank would be my last option.