Engine races Briggs & Stratton engine Model 204412 on MaxBoss 5500 watt generator. Engine races to max speed without the govenor cutting back. Checked the rod coming out of the engine hooked to the carb. linkage, and it does not move on its own but I can move it by hand thereby adjusting the speed. Seems the govenor inside the engine is stuck and not cutting the speed back. Is there any way of unsticking the govenor without opening the engine?

If the engine is locked, it could be any one of several things. Most are rather expensive, like: seized due to no oil; broken rod; bad valve, etc. An engine mechanic is going to have to troubleshoot it for you.

If the unit is older it could have heavy carbon in the cylinder heads, it could be a ring sticking and binding, do a compression test. Compression is high or mechanical binding.

Give it a shot of starting fluid. If it runs initially, then most likely the jets on the carbureator are clogged. You should remove the carb and clean/rebuild it.

Usually the cause of slightly low voltage like this is that the engine is not running at full operating RPM. Find the high speed adjusting screw on the govenor linkage and adjust the engine RPM until the output is 220V - 240V

Take a spray of carb cleaner and clean the linkage mechanism from the governor to the carburetor and make sure they move with out sticking.

You have to go to a lawnmower repair shop with your model code and type of your engine on the generator and buy a new gromet.

You may have exciting field broken. Look for a fuse or wire break.

Those voltage readings MAY be normal.

The AC waveform may cause your meter to read inaccurately. You would need to use a TRUE RMS meter to accurately read the voltage.

The siple meters actually read the AVERAGE voltage and then are calibrated to mulltiply it by the "form factor" for a sine wave. OFTEN these generators don't produce a clean sine wave. A square-ish wave will read higher on the garden variety meters.

Compare the brightness of a lamp comparing to when run on your utility.

The frequency depends on engine speed ... yours is running a bit fast...check it under at least half load and if off, adjust the govenor slightly.

I found a parts list for model 204412 at http://www.buysmallengineparts.com/