Hot start performance issues: Gas boiling at carb

[Big_Guys_baby]

It has been warm the past few days and after about 20 minutes or so of driving, I notice severe power decrease on the 46 coupe'.

After I was finished driving today, I popped the hood and saw that there was definitely some air/gas bubbling out of the hard line connection from the fuel pump to the carb, as well as around the gaskets between the upper part of the carb and the lower part.

The carb was a rebuilt unit from Carpenters that my dad put on, probably close to 8-10 years ago. The car did sit for at least 5 years with minimal running. I still have the original carb that was on the car when we got it, the throttle cable connection is busted off and it needs some serious attention, but I would love to get that one rebuilt at some point.

Regardless, I need some advice on tackling this and getting the fuel system running a bit better.

I have an external temp gauge, and the engine runs between 165 and 175 like clockwork, even when it was over 80 degrees today in North Carolina. I do have a cheesy little autozone air filter on it, not sure if airflow is part of the issue.

I have a clear inline fuel filter in the engine compartment between the hardline termination and the rubber line to the fuel pump, and I noticed that after driving a bit, the fuel flow is not steady into the filter and the fuel filter is mostly empty of fuel. Once the car cools down a bit and sits, more fuel seems to materialize in the filter and it is at least 2/3 full. I have been using an electric fuel pump solely as a priming pump with great results, the car fires up right away when cold!

I know I need to dig into this, not sure the best approach or place to start!

Thanks

Jeff

 

[G.M.]

Remove the inline filter and install a fuel pump with the gas bowl. A paper filter with a spring under it in the glass bowl makes a good filter. The carb boiling comes from heat of the intake manifold. Get a 1/2" vented carb spacer from Bob Shewman 1-610-933-6637 This will take care of that problem. The vapor lock in the fuel pump is from when the fuel pump gets above 120 degrees with the ethanol gas. This is hard to eliminate, you need to run 3 1/2 to 4 lbs cold fuel pressure. I say cold because the pressure drops as the pump gets hotter. Below 1 1/2 lbs the problem starts. The only cure I have found is a small fuel return line to the filler neck after the pump with a .070 restriction hole in the return line. G.M.

 

[41panelmark]

I have the spacer and I went with taller nozzles/and top, helped a lot. I also installed a pump near the tank that I switch on when any vapor lock occurs or to start when setting for a long time.