149 loses power until it runs some.
 

I have a 149. Until it runs for anywhere from 5-10 min , any load will cause it to bog down and I have to stop sometimes and let the engine catch back up. After a while it works fine. I should also mention also mention that the charging system is not functioning properly. The battery will not charge. I have tried a different volt. reg.. I took the S/G to have it tested and supposedly they said it was fine. Also I grounded the F terminal and it put out 16 volts while running. When it is not grounded, maybe 2 volt output. Is all of this connected.

I would suggest, that you make sure that the V/R is properly grounded. If need be, run a ground wire from the mounting foot of the V/R to the Battery negative terminal. The problem lies in or around the V/R. This is assuming, that there are no wiring issues (bad wires or connections) and it is properly wired.