The motor is a 115 hp 2004 carb 2 stroke. A dealer that, in my experience, has little ability to diagnose and fix a problem rebuilt my carbs because the motor was hard to start. That did not solve the problem and I went to another mechanic who fixed the starting problem with a simple ajustment to the choke plate. Now I have a surging problem. At about 4000 rpm and above the motor surges. It idles fine but above 4000 it will go from 4800 to 4000 then back up again. It does this for the first 20 to 30 minutes and after that I can run all day no problem. What could the dealer have done while rebuilding the carbs to cause this problem?