low top speed

Hello to everybody. I am a new boater who bought a 1995 Four Winns 190 Horizon with a 5.0 OMC Cobra last spring and we are loving it! I am a little disappointed with getting out boat to cruising and top speed. According to other posts and the owners manual my WOT is 4200-4600 for my engine but when I get there, we are only doing 25mph according to my gauges. There is plenty left on the throttle and the engine because I have got it close to 5000 rpms when getting my brother in law up on skis (300+ lbs). I had an experienced boater out with me to help me learn to trim out my drive but it hasn't helped much. He suggested getting a stainless 23 pitch prop but I can't imagine going from my current aluminum 21 to 23 will help out that much. Can anybody offer any other suggestions?

Re: low top speed

Get gps to see actual speed. As far as going to a 23 pitch he is just trying to get your wot rpms down in the recommended range. 25 mph seems slow at 4200-4600 rpm. Use a gps and get a true actual speed. bet ya find your going faster than you think.

Re: low top speed

Ayuh,... It sounds like the Tach is off....

Re: low top speed

Thanks for the suggestions, I probably won't get the boat out for another week or two but I will definately get a GPS to check my speed.

Re: low top speed

may be faulty speedometer, tach, improper pitch or a combination. Check your true speed first, then decide if you tach is faulty. If your motor is able to products rpm higher then the recommended 4600 then the boater is under pitched. Increasing pitch will increase boat speed if the motor is able to turn at 4600 rpm with new prop.