Pat;
The cold start valve is not the problem,It's job is done as soon as the engine is running.
If the eng. is popping through the intake on accel. then the mixture is probably lean.
On the left front of your eng. you will find a two pole temp sensor,install part#2015408034 on the green with red tracer wire, This is a 470 ohm resistor and is intended to richen the mixture during warm up.
The best thing to do would be to have the mixture checked after this repair.
MF