Highly suggest you toss the Hitachi over the fence. 

Put a Weber 32/36 DGEV on it and be done with it. 

GD

While I agree it could be a lot of different things, might I suggest you check the anti-diesel valve. Since the issue appears to have come on suddenly.

This is the large hex thing sticking out at 45° angle on the front driver side of the carb.

You should hear it click when you turn the key to ON, not started.

I accidentally left mine unplugged last night and the car would start with the choke but wouldn't run when warm unless the throttle was held open.

The valve can be bypassed by unscrewing it removing the spring and plunger and screwing it back in, until you get a new one.  Obviously if it's clicking it's probably not your problem removing it will surely break the ridiculously fragile wire so don't touch it unless your sure it's faulty.

On 9/29/2021 at 10:19 PM, Subi81 said:

While I agree it could be a lot of different things, might I suggest you check the anti-diesel valve. Since the issue appears to have come on suddenly.

This is the large hex thing sticking out at 45° angle on the front driver side of the carb.

You should hear it click when you turn the key to ON, not started.

I accidentally left mine unplugged last night and the car would start with the choke but wouldn't run when warm unless the throttle was held open.

The valve can be bypassed by unscrewing it removing the spring and plunger and screwing it back in, until you get a new one.  Obviously if it's clicking it's probably not your problem removing it will surely break the ridiculously fragile wire so don't touch it unless your sure it's faulty.

Thanks for suggesting that! I certainly would have given it a try, but I am actually now working on converting to the Weber 32/36.

I really wanted to make the factory Hitachi work, but I got tired of messing with it and decided the Weber would probably serve me better long-term anyway.