engine and drivetrain Solex 36/40

[Chippy]

Hi guys,

 

I recently cleaned a 36/40 on a car that hadn't been running for a few years.

 

It runs now, but the idle isn't very smooth and needs to be kept around 1K RPM or it gets very rough.

 

I have the idle mixture out 2.5 turns currently.

 

A mystery to me is what the screw on the right hand side of this photo is for (not my photo), and is it supposed to be fully turned in?

 

I plan to pull the idle mixture screw again and spray some more cleaner to see if I can clear any other grit out. Also going to purchase new plugs and reset the valves.

 

Thanks

Edited October 26, 2016 by Chippy

[arminyack]

That's just the setscrew for the venturi.

[Mike Self]

Usually those 1 bbl Solexes run very well, and have a particularly smooth idle (much better than the 2 bbl Webers, at least in my experience).  I'd look for a vacuum leak somewhere--try using either carb cleaner or an unlit propane torch near any suspected leaks; if the idle speed increases, either the carb cleaner or propane is being sucked into the engine from other than the carb throat.  That means there's a vacuum leak.  And make sure the vacuum ports on the carb are either in use (like for the dizzy's vacuum advance) or are plugged.  

 

High mileage carbs can have worn throttle spindles (the shaft that the throttle butterfly pivots on), so check around the two ends that protrude from the carb body.  

 

Of course make sure your ignition is in good working order: plugs, points, cap, rotor, plug wires before you start messing with the carburetor.  My late father-in-law, when he was teaching me how to work on cars 50 or so years ago often told me, "Mike, you mess with the carburetor too much.  90% of your carburetor troubles are in your ignition.  Check it first."  And that was good advice.

 

cheers

mike