I took my 74 BB in to the local shop to have them slap in a new fuel pump. They did that but in the short ride home I was blasted with gas fumes very heavily the whole way. I don’t have a fuel pressure gauge but the only thing I’m thinking it could be is too much fuel pressure to the carb. I have a 750 QFuel carb.
All the hose connections look good with no sign of a leak. The idle was running rough when I first started until it warmed up but the carb performance was a little off from usual.
I bought it new at O’Reilly’s and just asked for the stock mechanical replacement that cost about $40.
Does this sound like too much fuel pressure ?

 

Too much pressure to the carb will cause flooding and very high float bowl levels. Which will make the car run very rich
One would think running very rich it would run better cold and get worse as it warms up.
Without a pressure gauge, look at your spark plugs, are they black. Remove airfilter lid and observe carburetor while running. Triple check for fuel leaks.

 

4vettes is wise. My friend had a car burst into flames due to a fuel leak. Check like your car depended on it.

 

Yes a few people have tried to warn me saying be careful these cars can burst in flames and then look at me very sternly.

 

The fuel pump that you bought and someone installed should have three ports / fittings to it.

One port is a no brainer, the fuel line from the rear of the car.
The other line goes to the carb obviously.
But if the third port was not installed correctly, that could be the fuel odor issue.

 

I checked the plugs as suggested and they look excellent. I started it with the air cleaner removed and it appears there are excessive fumes coming up from the carb. Kind of a faint mist. The connections to the fuel pump look good, but the small hose looks like it may be kinked a bit at the entry of the fuel pump. I'll have to climb under it later to double check on that for certain.

 

When I installed my new engine I put a new pump on it just to be sure, and I was having fuel and starting issues as well. Checked the pressure and it was up to about 12lbs. Bypassed it and put an elect pump
on untill I have time to put a pressure valve on and re do the fuel lines. I've been told high pressure in the new replacement pumps happens often.

 

Ah. A clue!

When the small vent hose is pinched, it cancels the bleed-off, and the fuel psi rises a little.

 

I see the problem. A fuel line on top came loose during the install and needs to be reattached fully. I'll let you now how the fix works.

 

Do you have any pressurized rubber hose (between the fuel pump and the carb), or, worse, a clear glass fuel filter? That will get you some more stern looks from this Forum.

Please post some photos! Someone might spot something obvious that could save you some trouble.

 

Yes I have a clear plastic fuel filter mounted near the sending unit by the gas tank a mechanic installed without telling me.

 

Fixing the fuel line corrected the leak problem I was experiencing. It's a long story but I recently revamped the fuel line when I tried to install a smog pump. I had to feather the fuel line through the side of the smog pump and the valve cover as was done on the stock design. But since the smog pump is now removed I'll need to revamp the fuel lines all over again. Rubber fuel lines are a no-no?
I was concerned about faint fumes emanating from the top of the carb. It seems these fumes do eventually work their way back to the cabin.

 

Just replaced the fuel pump on my ‘68 427 and I did have a pressure gauge installed. The pump I received from Zip Corvette was from Carter and it put out 9+ lbs of pressure. I only ran it for a couple minutes but it was obviously flooding the engine. After I shut it down I walked behind the car and saw a cloud of smoke wafting across my yard, another sure sign it was flooding the engine.
Awhile back I installed a Carter “high volume” pump on my Dodge and it put out the same pressure. I installed a Holley pressure regulator on that and it held like a rock at 6 lbs, ran perfect afterward.
I’m presently installing the same regulator on my Vette .
I’ve read quite a few posts about the pumps made today putting out excessive fuel pressure.
I’d be willing to bet you’ve got the same issue.
Wouldn’t hurt to mount a fuel pressure gauge installed in the line so your not in the dark on this. We have gauges for everything else in the car but this is as important as diagnostic device as anything else and not that expensive. You might find that you need to mount a regulator in the line between the pump and carb. Again not that hard or expensive to do.
That is unless you’re super picky on how everything goes together.
Below is a mockup assembly of my setup I took today. Should have it together on the next day I can get back to it.

 

That might be too restrictive. Most inline filters are designed to go between the pump and the carb under pressure. A metal can filter is preferred. That’s not saying the filter location your mechanic chose is a bad one, just needs a different filter. Holley makes a “pre-filter” that is less restrictive and designed to go “before” the pump. I installed one in my car.

 

Interesting what you did there. I guess I don't have too mush fuel pressure it was actually a leak in the fuel line next to the carb where the mechanic tugged on it from below and then didn't check for anything on the top side coming loose. But I am interested in installing a fuel gauge and do something with getting a better in line filter.
I also noticed what looks like a shut off valve for the flow to the heater core? Not a bad idea! Every year I switch the hoses to loop back around in the summer to stop the excessive heat from the heater core in the hot summer. But that would save a lot of effort changing hoses! excellent!

 

I have one exactly like that. NAPA, around $27. I think it looks more automotive than some.

I hid the valve down near the starter area just before the hose enters the heater core. But still has easy access.
NAPA will want to know if you want a 3/4" or 5/8" valve.

 

I got mine at Home Depot. Good selection and inexpensive. Less then $10 if I recall. You can get a small one and hide it under the hoses. I turn them both off that way I know no extra heat in the cockpit.