My problem I how I solved it. I picked up a 96 Spi 580 for $200. I did the fuel system cleaning and replaced the tempo lines. Clean the carbs and rejet for a coffman pipe.

The ski would bog or surge at WOT and would get worst when the gas level was below half tank. It lead me to believe I was getting air in the fuel lines.

Maybe a pin hole in the lines??? Got home and tested the fuel lines by pressure testing with my pop off guage. I did this by pinching off the run line at the pick up and pumped it at the inlet for the carb. I've put 5 psi in this circuit and no leaks.

I was still convinced I was getting an air leak in that circuit. So I put a vaccum pump on it and found a leak at the fuel selector. It would leak in the run position. I tested by removing the run hose at the pick up and pinching it off. Then applying vaccum to the inlet port at the carb.

I replace the selector and now have a ski for the kids to enjoy.

I hope this helps some one in the future.