Carburetor or mechanic?

[Pr124spider]

My 75 spider has a 32 36 dfev Weber that’s only 2 or 3 yrs old and doesn’t have a lot of miles on it. Has electronic clutch and ignition.

Since I bought it, cold starts are poor. Takes 6 to 8 tries to turn over, followed by a very long warm up period, then runs smoothly. Mechanic tinkering has not been able to improve on this, (recommends replacing choke).

Setting the idle has been a problem as well. In three tries, mechanic 1st gave me car back at 1600 rpm’s (at idle), then 2200, finally now down to 1,000. Idle should be 800 to 900 I believe.

Finally, carb smells like gas all the time. Gas smell in cabin, in garage, even a couple days after driving. I can put my nose within 3 feet of the carb and smell gas.

So, knowing all that, would love to hear your insights and suggestions. My questions are…

If I have a new choke installed, will that resolve the cold start problem (if other contributors check out ok)?

A new carb with install is about $800. Replace the carb because idle set doesn’t want to take and gas smell will be rectified? Anyone recommend a better (more reliable, easier to work on) carb or stay with current type?

Could inability to fix the carb be more on the mechanic than on the carb itself? Is this carb particularly baffling?

Thank you very much.

[18Fiatsandcounting]

A few thoughts:

Since you have a 32/36 DFEV carb, that wasn't stock, so it means the previous owner installed the DFEV. Done correctly, it's a nice carb for the spiders. However, many people also remove a lot of the emission control items at the same time, which make the cars run poorly if not done right.

Since you have a high idle (choke fully off I assume), the typical cause of that is an air leak around the base of the carburetor, the intake manifold or one of the hoses leading to it, and sometimes various ports on the carb that weren't plugged or connected. Carefully inspect the large vacuum hose that goes from the intake manifold to the brake booster. Those hoses often develop leaks, and sometimes the booster itself has a leak. You can test this by temporarily plugging the port for that hose and seeing if the idle speed drops.

The smell of gas is often due to a vent issue on the carb float bowl. I believe the DFEV has a vent line on the float bowl, and this typically goes to the vapor recovery system (the charcoal canister). Do you have that charcoal canister? If yes, they do sometimes go bad.

As for hard starting, that could be somewhat typical for a mid 70s spider, but it could also be the choke or an issue with the fuel draining back down the line to the tank, and the evaporation of gas in the float bowl (which also causes the gas smell).

Someone who knows Weber carbs should be able to figure all that out, but such folks are getting harder to find as time goes on.

As for setting the choke, there are specs for this, and there's a guy on YouTube who describes the procedure. He goes by the name "Eldest Builds".

Hope this helps.
-Bryan

[Pr124spider]

Bryan, you’re the best. Thank you. Will ask my tech to read your reply. Very frustrating not having someone who can dial this in for me.

[geospider]

Iv'e got the same carb. have for years.
First check everything Bryan said.

New: they come with primary Idle jet: 60. I moved to a 50, which made the idle mixture adjusting much easier.
before, my idle speed adjustment was all the way off and idle still high. you can even use a 47 for more adjustment.
read the Mirafiroi site info on this. https://www.mirafiori.com/forum/

the choke on these kinda run until you kick them down.
to start, I will press the pedal down twice, which sets the choke and squirts some fuel with the accel pump, then turn the key. mine then idles at ~ 1500-1800 depending on outside temp. let it get to 150 deg and kick it down with a flick of the pedal.
if I haven't run for a few weeks, I turn the engine a few seconds to get fuel in the bowl, then go to previous process.

If going through the carb and checking everything, I would check the float adjustment.

This is a great start
http://www.redlineweber.com/html/Tech/c ... _best_.htm

Geo

[Pr124spider]

Geo, thank you very helpful. Will forward to my texh person who I’m making rich working on this carb over and over again.