Hi All -

Im brand new so go easy on me. Apologies if this has already been brought up recently. Any help would be appreciated. I’m stuck.

Here’s the sitch:

I’m just wrapping up a 5 yr resto on a 67 SS. Coupe. I put a 427 BB in and I’m almost ready to take it on the road. The carb is a quick fuels 750. It will start right up and idle fine for 5-10 min. Then you can hear it running of of gas and then boom she dies!

I get get out and look on carb sight glasses and they are empty!

Couple notes here:

i have one 3/8 feed line to mechanical pump. No return line. I did have to clock the fuel pump 90 degrees to make the hoses fit.

I don't have a fuel pressure gauge.

Is it possible the cap on gas tank is stuck or rusted and not venting? Is this common?

Thanks for any input!
Brian

 

Beautiful ! ! !

Unfortunately, not many people left here with the old school stuff.....

Is any part of your fuel line too close to the exhaust system, causing vapor lock as it heats up?

 

I bet there are a few spots where it’s close and she runs hot. I don’t know how to keep the heat off the lines.

Is is there a way to run a return line back to the tank - would that keep fuel circulating?

Maybe that’s a bad idea.

 

A mechanical pump on the engine pulls a suction on the line from the tank. That alone increases the chance of fuel vaporizing in the line. Add some heat through the line and it's very likely to vaporize the fuel, filling the pump suction line with vapor rather than liquid fuel. That’s why modern systems run a pump in the tank, to eliminate the suction line, and put the fuel headed for the engine under pressure.

There are insulation wraps available that you can apply to the fuel line to reflect the heat. You can also use heat wrap on the exhaust pipes to minimize the heat. And moving the lines a bit further away can help. If you are running headers, I wouldn’t recommend wrapping them.... potential for damage to the headers.

I'm not familiar with the issues or benefits related to adding a return line to a carbed setup. But it’s not going to cool down the fuel. That would just add another line possibly exposed to heat from the exhaust system.

You mention a possible non-vacuum relief (or non-functioning) fuel cap. That will increase the chances of fuel vaporizing in the pump suction line. Try running the engine without the gas cap installed.

 

Ten-4 - I will start with taking the gas cap off and go from there! Thx for the input. Might add a pressure gauge and regulator too. So at least I know what ball park I’m in.