Technical Purple ride

[1970 Fiat Purple]

Hello,
I have purchased a 1970 Fiat 500, we love it! But, lately the car will quit running, then after a while the car will start back up. I have rebuilt the carburetor and upgraded the ignition the electronic, all with no help. Any suggestions would be greatly appreciated.
Thanks!
Bill

 

[the hobbler]

Hello,
I have purchased a 1970 Fiat 500, we love it! But, lately the car will quit running, then after a while the car will start back up. I have rebuilt the carburetor and upgraded the ignition the electronic, all with no help. Any suggestions would be greatly appreciated.
Thanks!
Bill

Have you tried running the car with the fuel-tank filler cap OFF. It could be that the cap is not venting correctly, and therefore by using fuel you are creating a vacuum in the tank, which will stop fuel flowing through at the rate you need it to keep the engine running. By stopping for a bit of time, the tank could be "de-vacuuming" which will, again, allow fuel to flow. I accept that this sounds silly, but I have known it happen, and from this distance, it is difficult to diagnose the fault. Also, has the fuel system got an external fuel-filter? If it has, is it partially blocked? The engine, standard, has 3 fuel filters---tank-unit, top of fuel pump, top of carb---it doesn't need any more!

 

[heggae]

If there is a screw on the carb that adjusts the float level. That can also be the problem. I had one that did exactly that. As soon as it got hot. It would not run. Turned the float adjust screw a few turns. And that fixed it perfect. Not sure whether it raised or lowered it. But it fixed it. Can’t remember if I turned the screw in or out

 

[the hobbler]

If there is a screw on the carb that adjusts the float level. That can also be the problem. I had one that did exactly that. As soon as it got hot. It would not run. Turned the float adjust screw a few turns. And that fixed it perfect. Not sure whether it raised or lowered it. But it fixed it. Can’t remember if I turned the screw in or out

There is no screw on the 500s carb which adjusts the float level. The top=cover of the carb has to be taken off forthe float-level to be adjusted, and thenitis set. The only external 'adjusting' screws (2) on the IMB carbs are the idle SPEED adjust and the idle MIXTURE adjustment. Checkthatthe choke (or to be more accurate--cold-start enrichment device) is coming off. The operating arm for the device is on the side of the carb, and should be fully BACK when running without the 'choke' and the little lever between the seats fully down.

 

[heggae]

There is no screw on the 500s carb which adjusts the float level. The top=cover of the carb has to be taken off forthe float-level to be adjusted, and thenitis set. The only external 'adjusting' screws (2) on the IMB carbs are the idle SPEED adjust and the idle MIXTURE adjustment. Checkthatthe choke (or to be more accurate--cold-start enrichment device) is coming off. The operating arm for the device is on the side of the carb, and should be fully BACK when running without the 'choke' and the little lever between the seats fully down.

Great explanation. That adjustment was on an old holly on an old Saab. But in this fiat issue could the float need to be adjusted by The way you described if the other tips don’t work. My guess is that as things heated up it expanded. And basically flooding the carb. So float needs to be lower ?? Appreciate the education. Thanks.

 

[1970 Fiat Purple]

Hello All,
Thanks for the information, I will check all of these suggestions out. I will keep everyone updated.
Thanks!
Bill