prop help
 

I have a 28 donzi zx scorpion with mirage+ 25p problem is i am only getting 72mph(gps)@5000rpm. used to get 76mph@5200 before i had them refurb but I am not even close to the 80+ that donzi claims i should get. should i buy a brand new set and @least start from there?????

Both sets of numbers suggest good hook up and that the props are performing well. At least on paper. Your seat of the pants observations could be different.

The 80+ number can only be acheived with more HP. At least from the numbers you have supplied, HP is the only way to get there.