exhaust melt

I have a 2004 3D rfi and I have deleted the resonators and have it just straight piped it from the water box to the outlet. I am aware that this may cause it to be harder to start, but my question is that I have drilled out all the fittings in tune pipe (3) along with all the other elbow...

So bought two 2005 SeaDoo 3d skis used. Ran great on the hose. Took them home. Got them on the lake and 10 min they both had melted t fittings. The skis always had the tell squirting water. Looked like the fittings were replaced before with fittings from home depot. So they knew when they...