Last year on flat water going WOT (About 6000 rpm) I was able to get 29 mph on the gps and +30 on the boat spedometer.
This year, same boat, same load, same rpm and per the gps its about 25-27 mph.
Yes, I checked to see if the anchor was out
, and the prop is the same as last year and no damage to it that I can see and it was re torqued two weeks ago per the specs (@ 29.5 ft lb).
This isn't a serious issue as I don't run WOT a lot, and the boat goes real nice at 4800-5200 rpm, more so a curiosity item as to the loss of a few mph of top end speed for no outward reason that I can see.
any ideas out there???