Why would my engine be hitting 5900rpms? It reached it quite easily, but I didn't really seem to lose any power. I had a full tank, three guys on board and was peaking at 71, it was about 102 out and the lake water temp had to be close to 90.

Wouldn't the rev limiter be kicking in?

Tach is wrong most likely.

You should be all over the rev limiter by then....I would say your tach is wrong. I dont think its a good idea to spin a stock 525 that high things are gonna go boom

damn Griff you beat me to it

Was the boat or engine ever part of a raceboat?
Steve

Easy to check the tach. Grab an inductive pickup tach and clip it to a plug wire to verify the accuracy of the boat's tach. I had to do this recently as at idle my tach showed 800 RPM but shop tach showed 650 RPM. Just make sure the lead is long enough to snake through the hatch so you can run WOT with someone sitting in the back seat reading the shop tach.

My idle is 1200

Your ECM could be modified the stock rev limiter should kick at 5400 rpm

Also could be the AGI box I had one go bad and my tach read high