2001 135 fitch

[greenislandtuna]

I love these engines just last week put boat in water had it out for hard run 1st of season around 4000rpm the port engine would surge up and down could feel it and see it on tach gets up to 5500rpm starts right up idles no problems when put away for the season last year changed all my filters re-filled with gas and fuel conditioner just changed all the plugs out any suggestions I do believe it is fuel related but where do I start thanks

[boats.net]

Run a fuel pressure test when surging to see if steady, may need to clean VST.