I recently burnt out a distributer module/rev limiter (HP 500)
and seemed to lost 300 RPM/ 5 MPH after I replaced it, I'm baffled, Going to try DUI distributors this weekend & hopefully recoup my lost RPM's.

Hazy, Hot and humid his summer. Last summer in CNY was cool and windy. The lakes have been glass and the air is hot and humid. I've seen similar results this year, loss of speed and no changes. Like anything else in CNY, blame the weather

If you read Need-the-speed's last post, he says same RPM's. Everything else being the same (which he says it is), it looks to me like his prop slip went up (less speed + same rpm= more slip). The big question now is why??? Most of the posts (except Griff) are assuming a loss of rpm. Need-the-speed, Did you add anything to the boat that could disturb water flow? Like a new depth transducer?? You'd be surprised what could cost you speed. Especially when you have everything tweaked. I had a 17' speed boat that after a lot of tweaking did 72mph. Then one day I added a depth finder. I took the boat out and found I lost 4-5mph! (Radar). I removed the transducer right in the middle of LI sound (Quick release transom mount). I got my 5mph back right away. From that day forward, I learned the value of water flow along the hull

I'm absolutely stumped. I have not added any typ of device to the hull of this boat. This is really driving me nuts! Maybe I'll try my other props for kicks.

If the rpms are the same, I would lean toward a hook having developed.

Thinking about it now, when my boat lost speed, it also lost rpm (Prop slip remained virtually the same).
Griff, a hook could slow it down, but I would think you'd see a corresponding decrease in rpm's, and probably a difference in boat attitude. Need-the-Speed, are you sure the rpm's are the same?

Possibly, but not necessarily. If the engine is making its power, the hook will just make the boat ride wetter and with more prop slip.

5mph is still a ton to loose.

Would a drive shower sticking down an inch cause any speed loss?It's right inline with the edge of the prop. It's one of those single side showers.

take a 6ft. strate eadge , check the bottem for hook, thats a space under the center of your strate edge ,, or if you have a rocker, as the word implies fountain says 1/16in. space,. hook is worth 10 mph

Holy $hit 10mph!!!! I may have the bottom checked. Perhaps a good Blue printing is in order. Thats going to cost Maybe I'll just save the money and drink my sarrows away