Fuel Pump volume

[aliendude]

I'm stumped.    I had to change my gas tank as the 50 gal one was cracked.  
So now that I have changed the tank,  when I run up the rpms barely even a trickle of gas is flowing into the Fram G-2 clear filter up by the carb.  
360 2bbl.      

So I put in a electric pump back at the back to help.   Made very little
difference.    

I am stumped.   New rubber lines, no bent fuel lines, took off the in tank
pick up strainer.....   It gushes the filter full when first started.   Then as it warms up the fuel volume goes down.    Until the point it starts to pop in my
exhaust.  

I'm completely stumped.    Unless the old black rocks I got out of my salvage
yard 36 gal  tank were sugar.    Cleaned it the best I could at a car wash.....

Or it has clogged my power valve.

[AndyIlles]

Shaking my head A-Dude.  You're having more problems than I did.  Oh well.... ain't Clipping fun?   Think of it this way... otherwise, you'd be wasting your wad and time at the NCO club....

Hate to say it, but if you have an electric pump at the tank, you ain't getting any gas to it.... you're basically on the right track.

My guess is there was enough crud (likely a lot of it is "flaky") left in the tank to clog the intake.  Your clue is the junk the "new" tank was full of. Chances are even if you cleaned it, a lotta stuff got loosened when you car-washed it, and fell to the bottom later.  Guess where it all winds up?  Bettcha what's happening is there's a little "black mountain" (black-water holding tank-type... ya know?) right around the pickup.  Stuff falls off the pick-up filter when you shut down, so it'll pump fine when it starts up.... but then gets sucked back up and clogs the thing after the pump's pulling a little while.  Shut down.... falls off, runs fine.... gets sucked back up, no gas.... over and over.  Don't feel bad.... saw that happen to the 350 gal stainless steel tanks on an immaculate, "spare no expense" $3 mill racing Cigarette boat once.  Had us scratching our heads for a while too.  The owner had oversize filler necks installed, and whatever moron did the work forgot to clean all the metal shavings out from enlarging the tank openings.  Sigh.

One other thing to check.  After the thing stops pumping gas, leave it running and take the intake off the electric pump, stick it in a can of gas... see if it pumps then.  Possible there's something with the pump after it runs/heats a little while.  If it pumps.... see above.

[aliendude]

I thought about the clogged pick up tube as well.    So I took off the strainer and put a filter outside the tank.   I can see brown stuff that
settles to the bottom of the rear filter.    I figured I just keep changing the
filter outside the tank.   Strangely it was not even dirty.  
My tank pick up has two metal lines.  A large 1/2 in line that could take
a large 440 engine type G20 filter,  but was using a strainer on the 3/8 line.   The 1/2 in line
was capped.   So I put a G3499 filter on the 3/8 line ( had to drill out the end to slip it over the line )  when I did this the suction restriction pulled hard sediment rust out of my fuel lines into the front filter.    I changed that filter.   I took off the small in tank strainer filter cartridge.  
I can't use the larger 1./2in pick up line, as since it was not easy to
bend it, and it was capped - I cut it off with a dremel tool.   So it would now not reach the bottom of the tank.  
( the 36 gal tank is not as deep as a 50 gal.)

Your probably right.    My next think it to try running the pick up line into a jerry can.    

Does a mechanical pump have a strainer screen in it?    

Part of the problem is a capped off vapor can hose....as it works better if the gas cap is off.  
Since my old tank had a crack in it, it would work.  
Got to try to figure out the hoses to but them back onto the vapor can.

I could try to blow out the lines if I buy a air tank and chuck....

It was also suggested I bypass the mechanical pump for troubleshooting
purposes, and run off the electric...

I'm losing it......

[AndyIlles]

Yeah, that stuff can be frustrating.  But believe it or not, if you just approach it step-by-step with the process of elimination... you'll whip it.  Try this stuff, A-Dude...  Basically, you need to find out how far gas is getting (or not getting) to the engine.  At whatever point it stops, there's your problem.

AFTER the engine dies, leave the ign on (so the elect pump keeps running) and crawl back under the tank quick as you can and loosen the OUTPUT side of the electric pump.... see what happens.  If there's no or little flow... it's either the pump or something with the pick-up.   If there IS good flow.... obviously, it's a problem between the electric pump and the engine.

If there's NOT good flow outta the electric pump.... to determine whether it's the pump or pickup... have a little can of gas ready, and disconnect the INTAKE side of the pump and have it draw from the can.  If it pumps then.... it's your pickup.  If not, obviously it's the pump.

If there IS good flow pulling from the tank, shut her down and disconnect the fuel line from the INPUT side of the mechanical pump.  Turn the switch back on.  If there's good flow to the mechanical pump, then you've eliminated everything from there back - pickup, elect pump, filter(s) and the fuel line) as suspects.  If there's NOT good flow to the mech, look for a "hidden" inline fuel filter (I found onna those clear plastic ones on mine near the charcoal canister).

If there IS good flow to the mech pump, hook the intake line back up to it and take off the output and try again (don't start the engine yet... just the electric pump).  If there's still good flow, you've elimiated the mechanical pump as an obstruction.  If there's no flow through the mech pump from the elect one, though there's not usually any kind of filter inside mech pumps... obviously, there's a clog of some sort.  If there IS
flow (most likely), leave the output off and remove the input again and jerry rig a hose to the intake so the mech pump can pull out of a can of gas.... see what happens.  

If there's good flow through the mech pump.... check the line from it to the carb.

Somewhere along the line, you'll find your problem.  Like I said, from what you've said so far, my money's on crud in the tank that's getting picked up while it's trying to run... then dropped when you shut her down, and over and over again.

Another possibility, just to keep in mind.  Both electric and mech pumps have a pair of "one-way" valves in 'em... usually simple little caged, spring-loaded fiber disks held against a seat.  If there's a piece of crud holding either valve open in the electric pump, it can't work (same with the mech pump, though the elect should pump right through it anyway).

Anyway... see what I mean?  Just see how far you have good fuel flow.  Wherever it stops.... duh!!!  My money's on the intake though.

As to your charcoal thing, after taking mine out, I saw the nipples were embossed "tank", "purge", and either carb or bowl vent.  My "purge" one was capped off, and the bowl/carb vent one went straight to the carb base.  Since mine's a '76 360... can't help ya beyond that.

Good luck, A-Dude!!!

[handyman]

Hay Dude Andys right on with the check out but heres a little wrinkle while you have the fuel line off the elec pump put a tee fitting in it and run a hose to the out side edge of the couch and put a spring loaded vavle on it. works great if you need gas for your mower or another car, I;v got a hunch you mite have a picup problem like Andy said good luck shoule be easy to find also if theres still crap in the tank you can run a hose from the vavle to the filler neck and run fuel back to the tank untell it cleans its self worked for me when I got a bad tank of gas   Jim

[AndyIlles]

A-Dude and Jim...

That's a cool idea about having a gas spigot Jim... gotta do that one.  

I don't think your "recycling" fuel would work Jim... tell ya why.   Since he said he got tons of crud out of the tank when he pressure hosed it, I think what happened was it also knocked a lotta light flakes off the tank walls, and I'd suspect those flakes are what are giving him the Excedrin moment.  Though loose, they'd tend to stick to his tank walls and bottom when he poured stuff out.  After he filled up, they went to the bottom and are now gathered around the pick up, and like I said, are floating on and off his pickup depending on whether the pump's drawing.  So if he tried to pump it back through, it'd be the same problem.

I don't know how the pickup is on your tank A-Dude (btw... you have a name???), but on mine, there's a round plate with about 8 screws that has the sender unit and pickups for the genny and engine in it.  You need to siphon the fuel out in a way it takes the crud out with it.  You didn't say how much gas you have in it, but if it's above that opening, disconnect the intake from the electric pump and SIPHON the fuel below that through the fuel line (just remember it'll keep siphoning and you'll have to blow into the line once the level's where you want it).

Once the fuel level's there, gettcha a larger hose and siphon the rest of the fuel out with that, moving the hose around the bottom of the tank, particularly in the area where the pickups are - being sure the hose stays on the bottom.... sortta like wet-vacuuming it.  That should get most of whatever's in there out.  I'd guess it'll happen again, and you may have to do it several times in the next few months until you manage to get it all out.

I forgot to address your plugging the charcoal canister lines.  Though I don't think that's your problem, you're right - you do need a vent.  When I did mine, since I couldn't find a vented gas cap, I just extended the vent line from the tank to a T in the PCV hose between the air cleaner and valve... works fine.  

Good luck.

[aliendude]

Thanks for all the suggestions!    

Turns out it that this brand new hose I had put up at the mechanical pump
and looped with a nice gentle arc,  had collapsed.  
Stupid hose.....
This time I used fuel injection line that says GEN-2 on it.  
Maybe it will not soften up so bad.  

My electric pump never would prime itself.    Maybe if I draped the pick
up line under the tank to it......it would work.    For now It's Inop.  

I got this problem fixed.  

Now on to others.........

[handyman]

Dude I think you have a bum pump that thing should suck no matter where it's mounted or it's full of junk

[aliendude]

It's probably defective..........it wouldn't suprise me.   I'm going to
hook it up and run a line into a jerry can and test it...

Seems like everything I buy is cheapo........not as gooo as
stuff used to be.  

I still have to replace that fuel line at the back with better hose
later.     For now I'm tired of doing laundry and stinking like
gasoline........