521 fuel issues

[bilzbobaggins]

70 521 L16 32/36 weber carb

 

Heres the deal. Truck had been sitting for a month. My DD ate three valves the other night :fu: and figured I would use the truck.

 

Wouldnt start. Gas looked like shit and ive had nothing but problems with this ethanol junk. Drained all fuel, took carb off and cleaned. Replaced fuel filter. Tried to start. Wouldnt pull fuel through fuel line. If I drop the line in a gas can, It will run for days. So I try to suck through the fuel line(tank to pump and cant), so its stopped up. Fine. Go get some fuel line and run it from tank to pump. Now it wont pull from there. The tank is clean. You can blow or suck air through the new line.

 

Is my pump just weak you think? Bought all I think it can be. Any ideas are very much appreciated.

 

Thanks

 

Jeff

[boxboy]

I just went through this with my 1950 Ford. I thought my pump was shot, but I gently tried blowing backwards into the pump to see if I had leaks in the diaphragm. None. It held air. filled the carb bowl with fuel and it started and ran until no more gas in the bowl. Took the fuel line from the pump to the carb loose and started it again with fuel in the bowl and could feel small puffs of air coming out the line. All this to say that the pump needs priming and if you don't have it primed you aren't getting anything. So, I would:

 

Rig up your dummy tank and get the truck running

 

Then take loose the line from the pump to the carb and see if you are getting anything. Might want a catch container ready for this.

 

If you feel air pumping, try priming the pump. If you feel nothing, your pump is probably bad.

 

Good luck

[datzenmike]

70 521 L16 32/36 weber carb

 

Tried to start. Wouldnt pull fuel through fuel line. If I drop the line in a gas can, It will run for days. So I try to suck through the fuel line(tank to pump and cant), so its stopped up. Fine. Go get some fuel line and run it from tank to pump. Now it wont pull from there. The tank is clean. You can blow or suck air through the new line.

 

If it runs with a line into a can of gas then the pump works.

If the fuel line has been replaced then the tank outlet has to be plugged.

 

 

Try blowing into the tank with the cap off you should hear bubbling.

[bilzbobaggins]

Thanks guys. I can blow air from the pump into the tank and get bubbling as well as pull fuel through it. Might be a piece of crap that gets up in the outlet. Dunno yet. Had to go to work after my first post. Will get after this when I wake up. Tired of sharing my wifes car.

 

Thanks Again

 

Jeff

[bilzbobaggins]

Finally got her to run. Couldnt find a block in the inlet on the tank or any junk in the tank. Used my vac pump to pull fuel up to the filter, the rehooked and clamped. Fired up!!

 

Not to happy about the rubber line tho from the tank. Scares me in fact. Looking at getting a roll of steel line and redoing it.

 

 

What size is the stock hard line?

 

 

Thanks again

 

Jeff

 

Thought about running a return as well. I could just drill and add a fitting for the return on the tank, correct? But I do have the set of su's that ive been itching to install. Did they ever have a return on them?

[EricJB]

Had the same problem years ago with my 521. Turns out it was the vent tube was kinked. Also had one with the vent tube broken and it would fill the tank with water everytime I drove in the rain. Good times.

[bilzbobaggins]

Funny you bring this topic back up. Im fixing to go work at this again. She decided to stop idling and has a slight miss. Guess I will clean the carb again. Now that you mention it, this started after it poured for 5 Minutes the other night.

 

Its bumming me out. Had her idling at 650 ish(shitty tach).

 

Post any findings later

 

JEff