Over-revving at speed

Hello everyone. I stumbled across this forum looking for answers and I see there are plenty here! Here is my problem. I have a Hurricane 218R Fun Deck with a 200 HP Mecury EFI. The boat is 5 years old and looks like the day I bought it. Just recently it has started to over-rev at speed. I will be cruising along and suddenely the motor will start revving like it is out of the water. I slow down for a split second and it returns to normal. I did some searching and it seems to be ventilation or cavitation or a combination of the two. Am I on the right page here? My prop had a few knicks in it which I was able to file out and smooth. Will this fix the problem? I was thinking about adding a hydro-foil which also may help this problem and get me on plane a little faster. All the kids are 5 years older now and we are not planeing like we used to with the extra weight! Really looking foward to reading your opinions on this. Thanks, Al

Re: Over-revving at speed

Check for a slipping prop hub.

Ventilation makes obvious spray.

Re: Over-revving at speed

Thanks for the reply. Here is what I did. Bought a new hub and a SE 300 hrdrofoil. When I took the old hub out, it sure looks like it was slipping to me. There were some definate wear spots where it seemed to be slipping. So I hope this will correct the problem. Have no idea how this could have happened as I never hit anything. I also installed the foil to help with faster planeing. I hope to test it soon and will report back! Thanks, Al