winner bassboat
New member
I have Mercury 1991 XR6 150hp 1992 carb at high speeds it surges like its a light switch flipping on and off it gets to about 4500 to 5000 then all of sudden it kicks in and goes up to 5500 the drops back. if you slow down to 3500 to 4000 it runs fine it just started on my last trip out from the get go. I will be changing the fuel filter and rebuilding the fuel pump because I have noticed that if I let the motor set for couple of hours it losses its prim. I have checked the pugs they all look good except one it has some brown gunk built up on it. I have checked spark on all cylinders with a spark tester at idle and the all seem to have bright blue spark.
