1964 Cadillac rough running

[dabest2k]

Hey everyone, I'm new to this forum - so here goes my first post. Please can anyone help me! My 64 caddy intermittently runs really rough. It will run okay for a bit then all of a sudden it will cough and splutter - and I have to rev it to keep it running. If I let off the gas it will just die. It sounds like its a missfire. I have all new plugs and points. Think its a fuel problem? PLease help me! I am in England - and don't trust any of the mechanics round here - they only work on stupid 4 pots!

Paul.

[DFBonnett]

My first guess would be the carburetor float sticking.

[MagicRat]

Welcome to AF.

You may have a piece of dirt in the carb float bowl. At idle or at low speed, it can get sucked into the fuel inlet for the idle circuit, so at idle speed, it gets no fuel.

When you step on the gas, you are transferring the fuel draw from the idle circuit to the primary main jet circuit, which is unblocked. Therefore, you have an engine which will rev but not idle.

IMO rebuild the carb (its quite easy and you can get a kit on line.)
Be sure to blow out all the carb passages with spray can carb cleaner and compressed air. Also, change your fuel filter, and check the gas tank to make sure its not full of rust and will clog the carb again.

[dabest2k]

Hey, thanks guys for the help. If I take the air filter off should I be able to visibly see if the float is sticking? Sorry I'm a bit a newbie when it comes to carbs,

Tar
Paul.

[maxwedge]

No, all the components are internal. Based on that query, if in fact the carb is the problem, you realy should have an experienced person do this for you. If this is a Rochester 4GC, they are somewhat complex in respect to the number of float settings.

[DFBonnett]

Originally Posted by dabest2k

Hey, thanks guys for the help. If I take the air filter off should I be able to visibly see if the float is sticking? Sorry I'm a bit a newbie when it comes to carbs,

Tar
Paul.

What you should see is the vent tube for the float bowl. Sometimes spraying a good dose of carb cleaner directly into the tube down into the bowl then letting it soak for a while will free things up if that is the problem.
BTDT.