noisyone wrote: . . . even at full throttle, the carb throttle plate only is only about half way open. Is that normal, or should it be opening all the way to the max?
Engine running or not? If not running, carb should be wide open. If running it should only be part way.
I notice your choke isn't fully open. The engine should be warm enough to open the choke before dealing with this.
Have you pulled the drain plug on the carburetor and opened the fuel valve to make sure you have a good solid and continuous stream of fuel?
Have you checked the shaft that comes out of the left side of the governor for a good fit at the inner end? If it is loose, surging will be difficult to eliminate. There have been previous discussions of how to fix that if it is a problem.
Earlier in this thread, there was discussion of adjusting the linkage between the governor and carb. Have you done that? It will have to be redone if you have to fix the problem in my previous point.
Once all the above is in order, make sure the governor to carb linkage moves freely without any binding, rubbing on other parts etc.
If it still surges after all the above, there is an adjustable bumper spring on the front side of the governor. You can turn that in a little (like 1/2 turn) at a time to eliminate the surging. You may have to remove it completely to inspect and clean it before it will work properly. This is very close to the fan, so shut the engine off to make adjustments.
By the way, your tie rods are not properly installed. They should cross each other at the center.
