hard strating when hot-2

[DutchEdwin]

When the car is hot, it is hard to start or will not start at all.Took some time today to find the issue.

The carb. shows no percolation. Not drop of fuel will appear at the nozzles.

Because the car tends to start 1 time and will not after that, I disconnected the fuel line at the glass filter bowl, just before the carb. to see if it gets any fuel (see picture, the car is finished now so fenders and hood present). Result: There is no fuel coming when starting. When I look at the plastic fuel filter mounted before the fuel pump I sometimes see some foam/micro air bobbles appear for a short time (1 stroke of the pump).

Now I guess the pump is bad or there is a vapour lock in the pump. I can change the pump. But more important is, what can I do if there is a vapour lock in the pump?

[55 Fargo]

Edwin you can change thge fuel pump, make sure you have a heat shield, insulate the fuel lines from pump to carb.

Another relatively easy fix is to install an elecric fuel pump, just for start ups and for emergency back up, I think that would work well...........Fred

[greg g]

If there are bubbles in the gas, you might have a very small air leak between the pump and the tank. It may not even show liquid, as the gas might be evaporatig before a drip can form. However the suction from the pump will pull air into the line. This breaks the suction, ad if there is air in the diaphram area of the pump, it will prevent the proper amount of gas flow. Take a really good check of the fuel line from the pump all the way to the tank, looking for any dampness and tightening any of the fittings along the way.

[Jim Saraceno]

Do yourself a favor and test the fuel pump pressure. Assuming you have a vacuum meter, it should also have a pressure side. I believe the spec is 4-5#s. The other test is a certain volume of fuel withing a certain number of pumps.

If those tests pass, your problem is somewhere else, if not, its the pump or an obstruction.

[Joe Flanagan]

X number of strokes from the pump should produce Y ounces of gasoline. The actual numbers are posted somewhere on this forum. I seem to recall that you count twelve pulses from the pump and see how much gasoline that puts into a plastic container that you hold beneath the outlet (disconnected from the carb).

[greg g]

12= 6 to 10 ounces (280 milliliters?)

[DutchEdwin]

Thanks for the posts. I'll try to measure the pressure and volume.

Just a thought, as the pump does not deliver fuel when hot, but plenty then cold, could it be the lever is getting stuck and does not moving the diaphragm enough due to heat, or one or more valves getting stuck due to the heat?

B.t.w. the micro air bubbles that appear in the fuel filter are on the pump side of the filter, like air is pushed back in from the pump towards the fuel tank.