This is what I have found. The vent tube on the top right of the carb has a casting problem and is still solid. My new 525 would not run off choke. I made a big jet change and nothing changed. I took the vent hose off the top right and found it was still solid. I took a .078 drill and drilled it out and now it runs fine off choke.
I did change the main to a 185 and raised the needle one clip
I did change the main to a 185 and raised the needle one clip