Fuel problem

O

Oilslickwillie

Senior Member
Hello. I now have another problem that I just discovered. Not sure what it is yet. Been working on my carb and got it running again when I noticed what I think is a fuel problem. When my car is running I noticed that my big clear fuel filter did not have much gas in it. I watched it for a while and it got almost completely empty and then all of a sudden it bubbled and partially filled up with fuel again. Let it run awhile and did the same thing, got filter almost without any gas in it, then when almost all gone, bubbled and filled partially up again. Is this a sign of a bad fuel pump, plugged fuel line or what. Any ideas out there.
 
Forgot to add, metal line from gas tank, then rubber hose to fuel filter, then rubber hose to fuel pump inlet. Next, metal line from fuel pump outlet, then short rubber hose from that metal line to carb filter. Hose looks new.
 

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Just did some more checking and fuel pump had a little gas on the outer seam. Guessing that it's leaking there and most likely the diaphragm is bad. A bad diaphragm or leaking air is why filter is getting low on fuel. Update: Noticed after searching further that the pump is putting out a fine mist spray so guess I'll be putting on a new pump.
 
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I generally replace the fuel pump and at least the water pump when I acquire an old car, especially if the car has sat for a while. Cheap insurance.
 
Well, purchased a new fuel pump, new filter, new metal gas line and installed it today. Fired the car up and with a little carb adjustments it ran real good. Took it out for a drive and got on it pretty good and no problems. So why am I posting this you guess. Don't think it's a problem that I know of but here's what I noticed. With car running at idle, the clear fuel filter runs the gas all the way down and nothing in the filter that I can see. After running for 30 to 40 seconds, the filter fills up at about 3/4 full and then goes through the whole routine again. Car still runs smooth, doesn't hesitate or anything. Is it normal for this to happen as I described? If filter was not see thru than I would never know this was happening. Anything for me to look into or should I just ignore it. Member Melisa mentioned that her car does the same thing with no problems. With my old war injury acting up I had a hard time working on it today so guess I'm hoping all is well now.
 
Your Experience with the filter is not unusual.,,, probably related to the action of the carb float at low engine speed.
 
Mine did that. Had a leak in the fuel line coming out of the tank letting air in. Found the leak and repaired it. Now it drops to maybe 1/2 then refills.
 
Rubber hoses most often develop cracks and will pull a little air in with the fuel and could cause what you see. I would replace all the rubber hoses which should set you back less than $10 including the clamps.

I'm not big on plastic or glass filters, I'm a little AR about them from my stock car days. I like the steel ones that Moroso makes.
 
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