Briggs straton ohv on tiller , govener will not work, runs at high speed all the time, starter rope has become extremely hard to pull, will not spin engine.

The hard to pull, will not spin the engine issue could be because you need a valve adjustment. A valve adjustment is critical because it enables the built-in compression release on the Briggs OHV engine to function correctly and enable an easy start; plus of course, smoother running. Remove the valve cover and adjust those valves at 1/4" down past TDC on the power stroke. You WILL see a difference in the engine once you do the adjustment.. Here is a Briggs spec chart which has those values for their engines. Yours should be listed in the OHV engine section.

http://www.briggsandstratton.com/engines/support/frequently-asked-questions/~/media/71BB9DA0BD4D4C19A0DA611923A0B80A.ashx

Here is the Briggs recommended tutorial on HOW to adjust those valves. Scroll down this page to "Adjusting Overhead Valves"

http://www.briggsandstratton.com/engines/support/frequently-asked-questions/Servicing%20the%20valves/