I have an evinrude 200 hp outboard. It has an aluminum 15x17 pitch prop, WOT it turns 6000-6200. I updated to a 15x19 stainless prop Power Tech OSS series, it is a used prop and I cannot get over 3000 rpms, it appears to struggle so I replaced it and but the 15x17 and it runs back at 6000. Can this power tech prop have been modified to a much larger pitch and is there a way to measure the pitch. Should I try another prop with a 19 pitch?