Working on a Briggs 190412-3098-01 880122110. I have the engine running and runs quite well. The issue I am having is that it will only go to 2000 RPM. I have adjusted the speed control with no effect. I ran the throttle manually and with the throttle plate as far open as it will go, I can still only get 2000 RPM. I have had the carb apart and it is clean and good. adjusting the low or high speed adjustments will affect the running of the engine. It has a new air filter on it. This engine is on a generator so I need to get the 3600 RPM out of it to run the generator properly. Any ideas what to check or might be wrong? I am wondering if the compression is low on the engine will that cause this problem. When I pull the starter rope there doesn't seem to be much resistance, how ever when the engine is running it runs good. The engine starts good usually with out the choke. Thanks for any thoughts or advise.