kitecop917
Cadet
- Joined
- Apr 2, 2015
- Messages
- 13
I have a 2003 proline 22 sport with a 2003 Mercury 200 XL SWB (carbed) and I have been to the moon and back with this issue. When I got the boat the guy had a tiny 4 blade 17P prop on it. It would turn in excess of 7000rpms so I changed it right away. I picked up a stock SS merc prop in a 19p with a larger overall diameter. With that prop im still able to rev over the max RPMs and im only getting 26mph at 5000rpms. I picked up a 21p mirage plus and it is giving me the efficiency im looking for but one major issue. Once I hit 5000rpms with that prop on, the engine immediately drops the rpms down to around 3000 and then continues to go down from there. If I get up on plane and stay at 4600rpms or under then I get no drop in rpms. im running 34mph at 4300rpms with the 21p. So one, why would the 21p prop cause the engine to drop at 5k and two, why such a huge performance difference between the 2 props. I should only see a difference of about 400rpms from a 19p to a 21p right? not over 1000rmp difference? Also, I just all the fuel lines and inline filters. However I don't suspect a fuel problem because there are no problems with the 19p on there its just not efficient. The motor idles fine and runs great aside from the rpm drop with the 21p prop.