Do you mean that (a) the horn was sounding warning you about imminent guardian mode being triggered or (b) motor winds to about 6000 or so and wont go any further due to the ECU backing off on the power a bit?That is in the range of sub-10 percent prop slip from a quick mental calculation and from my experience running a 25p fury 3 on a 1.75 gear case myself. Might be the right prop for hot humid summer weather. That being said, I am running a 26p fury on my 08 classic with a 200 pro xs and I have not seen any reason to drop back to a 25 yet, although I have not run it in temps beyond 90 degrees so far. Dont own a cougar so I cant directly respond to what specific prop will be best, but any time you hit the rev limiter with reasonable slip (which you seem to have) next step is always going up in pitch. Just remember the summer which can be a double-whammy. First, humid/hot air contains less oxygen than cool/dry air. Less oxygen means less power per stroke. And less power slows the motor/prop down. And then you get the second whammy, reducing RPM can drop the motor out of its max power band, further slowing the prop and boat down. Ideal approach is to prop right up to the rev limiter (which should be 6000 on your 250) during the cold / dry winter temps, and then when the hot/humid summer temps hit, you will lose a couple of hundred RPM but still will be in a reasonable RPM band to avoid the second whammy above.2008 Pantera Classic2014 Mercury Pro XS 200
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