Hi Alan, welcome to Outdoorking.

What happens if you increase the idle speed setting? If it just will not run below almost full speed (3,000 rpm), we get one solution, whereas if it will run at idle speed (2,000 rpm) but needs more throttle to achieve that speed, we get another one.

If it simply will not run slowly but is fine otherwise, my first guess as to what has happened is that the idle jet is blocked. It is only 0.35 mm diameter, and if you have been less than scrupulously clean in your refuelling operations, this might be the outcome. Here is a previous thread on the subject:

https://www.outdoorking-forum.com.au/forum/u...p;Words=gcv160&Search=true#Post38602

That engine had a more severe case of dirt-in-the-fuel than yours, so it had lean mixture symptoms as well as a blocked idle jet. Yours should be easier to fix, since there is a good chance it just has one simple problem.

Please continue this thread, keeping us posted on what you find - we are here to help, and every thread should end with a solution.