Power loss, real or imagined?

[Kurt V]

I have a 1989 Bayliner with 2.3 Ford and OMC cobra outdrive. With full tank of gas and three people I have always managed to run 35 mph as determined by GPS. Last weekend had the boat out and now I could only get up to around 29-30 mph. Has fresh gas, starts right up, idles fine, gets up on plane just fine, not sitting any deeper in the water than it ever has, just doesn't go as fast. I can trim it right up to redline. Any suggestions?

 

[HopinImFloatin]

Re: Power loss, real or imagined?

with all other variables the same, if indeed you are achieving the same WOT rpm as you were before @35mph, it becomes math. RPM and pitch determine speed,same rpm and prop pitch should achieve same speed unless (a) prop has become less efficient...dinged, dented etc..., or(b) there is more drag from the boat from excess weight making the prop effiency? sp less, or maybe really dirty hull, or even different water conditions. From what i understand, very smooth conditions will effect speed due to drag. Just my thoughts, could very well be wrong.