[QUOTE=gunna;1671981]Because it is the RHS trim tab that effects the LHS bow attitude and vice versus. I know of 2 boats that have it set up inversely because they can't get their heads around it (brothers) so Scottars thoughts may not be that far off and worth a check. My own brother was shown by the dealer to trim the motor out to 4 stops on the gauge when he bought it, I could never figure out why he looked so closely at his gauges once he was under way, after a couple of runs I suggested a bit more trim out and the boat would ride better, then he told me and the penny dropped. I asked him to trim it out and once he did the revs, speed and attitude all improved. Some bloody dealers.
Noelm asks the question I was going to ask, and as Lovely80 mentions my Allison due to design flaw had a similar issue, now resolved, with water getting into semi sealed compartments, I spent a long time figuring it out.
Big E suggestion will give you and idea of where to start, don't start grinding or cutting anything until you are certain what the problem is.