The Stovebolt Site Forums The Shop Area Engine Shop Carb issues

after an entire summer with no problems, the cooler weather has given me a project as soon as I figure out what to do!
1948 chevy 1/2 ton with 235 3 speed on the column.
one barrel carb with manual choke...
In this cooler weather it is hard to get the engine running right. It cranks up with the choke out but if I try to drive it bucks and stalls... smells rich but when I push the choke in it quits...
after letting it idle a while it drives fine with choke all the way in etc.
got a thought ??
thanks
Jimmy

You need heat in the manifold to help vaporize the gas until the motor warms up. There's a number of ways to do that, but the basic idea is to get heat to the intake manifold as soon as possible. Some manifolds have water jackets to take care of that, and often the plumbing rusts and people put plugs in the holes, not knowing what their function is.

Sometimes a "heat box" is built around the intake, using metal to form a box around the base of the intake and then feeding exhaust manifold heat into the box using either convection or a tube.

Here's some stuff on the site that might help:
http://www.stovebolt.com/bboard/cgi-bin//ultimatebb.cgi?ubb=get_topic;f=2;t=008158
http://www.stovebolt.com/bboard/cgi-bin//ultimatebb.cgi?ubb=get_topic;f=5;t=000554

powerband,

On the surface this sounds carburetor related. I would check out my heat riser assembly. I think most of these are frozen open, and if yours is, it might be helpful to get it operational to help heat the carburetor quicker.

It might be a good idea to take a look at the condition of the ignition system. Sometimes humidity and dampness go hand in hand with colder weather, and this can cause a "lightning show" with the cap and wires.

As the engine warms up and things dry out, it will return to normal. Some folks will start their rig at night or in a dark garage to catch a glimpse of the arcing and sparking under the hood. Good luck.


Stuart

Thanks for the tips.
I will begin with the heat riser
assembly...
and see what happens.
Jimmy

I have always started my engines full choke and run them till warm 1/4 to 1/2 choke. A heat riser will cause poor atomization of fuel on a cold run if stuck and will allow the intake to warm faster if working. Now if you live in the snow belt the heat riser is important for short drives.

To me the condition sounds normal, if the choke is pulled all the way out and you try to drive it its gonna buck, snort, and smell like fuel. Try 1/4 way out after start till warm. If it isn't better then worry about heat riser.