You said you installed a "new" fuel pump. Do not assume that it is functioning properly. They are ALL complete junk straight from the box. I am not exaggerating. I and others here have had new fuel pumps fail in a few hundred miles or not even pump any gas at all after installation.
The only pumps worth installing are rebuilt originals or rebuilt after market pumps made before about 1990.
First, check your fuel pressure at the carburetor. It should be between 2-4psi. No more, no less.
When my first new pump gave up the ghost, it began with rough idling, stumbling, stalling, etc. Finally it wouldn't restart and I went down the road of looking at everything else because, "it's a brand new pump, no need to check that."
