1962 Super 90 Unable to idle
 

I have a friend who has a beautiful Super 90 with idling problems. We have gotten it closer by setting the timing and points as well as synchronizing/setting the solex carburetors, but we are still left with the following symptoms:

Hard Starting. When cold, the engine has to be cranked at least several times to get going, even when it had been running the day before so that the float chambers should be mostly full. After a week of sitting, it seems he has to crank it about 20 times, to the point that his gel battery is almost dead before it starts.

Dropping off at idle. I can get it to idle satisfactorily at 1,000 RPM for about 30 seconds, maybe a minute, but then there will be a slight carb backfire and the RPM's will slowly drop lower until the car dies in about 10-15 seconds. This can be averted by running up the RPM's and then starting the process over again.

With the above in mind, I thought it might be a fuel delivery problem. We disconnected the fuel line and the fuel pump pressure measured 1.3 PSI when cranked for about 20 seconds. We got good flow, but could not get the pressure any higher.

I think the pressure is supposed to be 2.4, but I did not know if this was being measured with the engine running.

Any ideas much appreciated!

Rebuilding the fuel pump is trivial (at least it was on my '65 C) so you may want to do that. Or, run an alternate fuel source using a gravity feed to brign the pressure up for testing purposes.

Thanks, we will give it a try! Is there any particular height above the carbs to hold the fuel supply in order to duplicate the 2.4 psi, or does that matter?

An approximate height to hold the fuel supply to duplicate a static fuel pressure of 2.4 psi would be about 90 inches.