hi I have a victa razor mower with a vsx 160 two stroke eng, 2005 model.It has never throttled properly in my opinion since I have had it, It would rev too slow for cutting grass along with surging and idled to fast when you went to empty the catcher. upon searching the forums and info made available by bruce,I changed the diaphragm spring in the carby from the original red spring to a yellow spring part no cro 3643a. This will increase cutting rpm and make the idle a little slower.I did try a green spring but it reved too fast, parts are available from your victa dealer rgds graham
