Hi Peter
I am making the assumption here that you actually are running a Carter W1.
If so... it sounds like you may have at least 2 problems (maybe more) as a result of mixing carburetor parts.
You may have the wrong metering rod for your carburetor.
And it probably isn't timed properly to the throttle opening.
Also, what is your float level set at?
We need to know what carburetor you actually have (there are many models of W1).
If there was still a tag hanging on one of the screws (which is highly unlikely), identification would be simple.
If there was still a visible number stamped into the flat surface of the bottom flange (also not very likely), that would also make it simple.
Outside of that, pictures of the carburetor from several angles, will help.
Once we know that, we'll know what metering rod you should have.
A special gauge is needed to set the timing of metering rod opening in relation to the throttle.
All that said, if you have little experience with W1's, it may be easiest to have your carburetor rebuilt by someone who knows what they are doing like Chipper.
If you would like to try a few things yourself, we'll try to help you with that too. :-)
PS
The gauge you will need is part number T109-25 and will look like the one below.
You can find one here:
https://www.ebay.com/itm/185478582006?epid=12051024663&hash=item2b2f628ef6:g:ZKYAAOSwRQpit38A&amdata=enc%3AAQAHAAAAoHfFQtFKXkwKNN9yLFscpFZtG8OvPiEmE%2B%2FYixqPPkThzE9zQYutVDbyIdtgX8F3F4xCaErh0tQGmPVj21YCtkm5mu3lMuUrzdmSPo2oKt%2B2OMTfRQe35j6lNcEXMSwDGhol2ffOgWNTTf1zIewkfkpYl0v7g74xvjEPmrb0%2BMwY22cbwKy4dyI7or43ERd8PiGMbtlqwfGk3t8KYdA5l4I%3D%7Ctkp%3ABk9SR4Ccl7jNYQ