Idled poorly, ran great - now neither 75 spider

[dirkdantuma]

After cleaning and replacing every electrical connector, my 75 spider ran pretty well all last summer except it never idled quite right. It would sometimes die at a light if I didn't do the old heel-toe trick with the gas peddle or pull out the throttle. Rarely when it did die, it would not start again without waiting for an half an hour or so, then it would start-up and run fine. So this summer I decided to take a look at the idle problem. Found the carb was loose and the PO had put in a 8mm idle stop solenoid when it required the 10mm (I guess it change half way through the 75 model). I tighten up the carb, replaced the solenoid and now it does idles but roughly, and when I give it gas, it sputters, chokes, and dies. I've changed the filter, checked the pump, changed the plugs and no change. For one brief moment as it was idling, something click and it smoothed out and rev up beautifully and then just as quickly went back to sputtering and idling roughly.

Oh great and knowledgeable Fiat enthusiasts, what say you other than loosen up the carb and put the old solenoid back in?

Thanks
Dirk

[dirkdantuma]

One other thing I forgot to mention is when I disconnected the fuel intake from the carb to check whether it was pumping fuel, it idled smoother and didn't die until I shut it off after my jar filled up with fuel. What does that mean? Vacuum?

[So Cal Mark]

by disconnecting the fuel line, the level in the float bowl would drop, leaning out the mixture. It sounds like maybe you have a bad float or needle valve or the float may be misadjusted. Did the old spark plugs look black?

[dirkdantuma]

Thanks Mark for the post. Yes the plugs were black. So I how hard is it to take the carb apart and get to the float mechanism? How hard is it to make the adjustments with just regular tools? It also has the hot water nipple for the automatic choke broken off so the water tubes are just looped. Are carb parts readily available or do I need to buy a refurbished one?

BTW the site looks great and it must be a lot of your doing since I see your name all over it. I know the site hasn't always been around but it when it was, it was always very helpful. So thank you very much for you efforts!

Dirk

[So Cal Mark]

the broken choke nipple could be the culprit-is the choke plate open? If not, it will run very rich. Not sure if new choke covers are available, but it shouldn't be too hard to find a used one. I probably have one. It's not hard to remove the carb top, but you'll need to diagnose whether the float is bad, needle valve is leaking or the float just misadjusted.

I can't take credit for the site or looks of it, that is all Evan's doing. I'm just the lowly moderator

[dirkdantuma]

The choke is fully open so I'll take a look at the float. As long as I'm tinkering, I might as well replace the choke cover. If you do have one, please email me the cost and I'll send you a check. dantuma (at) comcast.net THANKS for all your help!