Now that I think about it - The surging may be from a bad connection at the mounting swivel tab. The instructions I have are very insistent on hot having a gap between the long hex-nut and the swivel tab that replaces the original linkage mount. I have done this twice. On my boat I got lucky - but had to flip the swivel tab so that I could thread the long hex nut onto the cable - and it just hung on by a few threads. The second one I actually got wrong and it was surging. A more expert installer reviewed it and was able to adjust it correctly. I bet if you review you documentation about the connection of the hex nut you may get your answer. I had some questions and email PP and they were very quick to respond.