Technical Slowly dying when idling

[The Williams]

Hello,

New to the forum. Have moder Fiats, but just acquired my first classic one (1971). It starts fine, and I've been in it when it's run fine. When I got it home, I started it and if I don't continue to press the gas, it dies within a few seconds. Choke is still on.

I'm assuming the idle speed is low, but it's been a long time since I've fiddled with carbs and I'm not really sure how to adjust this one. Any instructions on that or tips in general is greatly appreciated.

 

[Goldnrust]

It's possible nothing is wrong.

Does the car idle nicely when warmed up fully? My 500 idles fine when hot, but finding the right amount of choke to idle happily when cold is a bit more challenging. The hand throttle helps here, as it means I can have the throttle just held a crack open, to lift speed a bit in that partial warm stage to make sure it doesn't stall.

 

[the hobbler]

It's possible nothing is wrong.

Does the car idle nicely when warmed up fully? My 500 idles fine when hot, but finding the right amount of choke to idle happily when cold is a bit more challenging. The hand throttle helps here, as it means I can have the throttle just held a crack open, to lift speed a bit in that partial warm stage to make sure it doesn't stall.

The 'choke' (it is not really a 'choke' as it has no 'choking' butterfly----it is a fuel enrichment device) only needs to be used when starting the car from cold. You said that you had the 'choke' on AFTER your run in the car---how does it idle, when warm, with the 'choke' off?

 

[fiat500]

I'm not sure what I'm looking at there, and from what angle, but that doesn't look like the regular Weber carb. on a Fiat 500.

 

[The Williams]

The 'choke' (it is not really a 'choke' as it has no 'choking' butterfly----it is a fuel enrichment device) only needs to be used when starting the car from cold. You said that you had the 'choke' on AFTER your run in the car---how does it idle, when warm, with the 'choke' off?

I had the choke on while starting the car. If I took off the choke, it would die quickly.

Update: I've got her starting and going, but the idle problem is still there. I did a couple of miles yesterday with the choke off, and when I stopped, it seemed to idle fine. When I made it home, she seemed to pewter out with clutch in and stopped while waiting for the garage door to open. Gave it some gas and it was good for a handful of seconds more. Rinse and repeat.

 

[The Williams]

I'm not sure what I'm looking at there, and from what angle, but that doesn't look like the regular Weber carb. on a Fiat 500.

That was my thoughts as well. trying to diagnose which one I actually have. That way google can be my friend.

 

[Goldnrust]

It does sound like your idle speed is low. The screw circled in red is the idle speed, try turning it in a little to raise the idle speed.

Circled blue, will be the idle mixture screw. When the car is good and warm and you've got the idle speed up a bit then you can try adjusting this. Try turning it clockwise 1/4 of a turn, which will lean the mixture a little. Give it a couple of seconds and see if the idle speed raises or falls. If the idle speeds up or stays the same, you're going in the right direction. Keep going bit by bit till the idle speed starts to drop, then turn it 1/4 turn antilock wise, till it picks back up to a stable idle.

If the idle falls on your first adjustment then the carb is already too lean, go back to where you started and try a 1/4 anti clockwise (richer)