My 525 builds
#21
Platinum Member
![](https://www.offshoreonly.com/forums/images/icons/platinum_member_star.gif)
Thread Starter
#24
Platinum Member
![](https://www.offshoreonly.com/forums/images/icons/platinum_member_star.gif)
Thread Starter
![Default](/forums/images/icons/icon1.gif)
The problem with running them with hours and week valve springs is the valves float little and beat the crap out of valve train. I would at least change valve springs every 200ish hours IMO.
#26
Platinum Member
![](https://www.offshoreonly.com/forums/images/icons/platinum_member_star.gif)
Thread Starter
![Default](/forums/images/icons/icon1.gif)
5mph gain. Best is 90mph now. Will run 85 to 87 loaded every day. Before was 78 to 80 loaded and 85 perfect conditions. Have almost 40
hours on engines now and run really nice.
hours on engines now and run really nice.
#27
Registered
![Default](/forums/images/icons/icon1.gif)
These dogs can hunt, I can vouch for that! One of the funnest rides I’ve been on.
#29
Platinum Member
![](https://www.offshoreonly.com/forums/images/icons/platinum_member_star.gif)
Thread Starter
![Default](/forums/images/icons/icon1.gif)
XR's. No issues yet. Figure Mercury puts them on 600sci motors and I am similar in power. I am careful getting on plane but let them rip when rolling regularly.
![Smilie](/forums/images/smilies/smile.gif)
#30
VIP Member
![](https://www.offshoreonly.com/forums/images/icons/prop.gif)
![Default](/forums/images/icons/icon1.gif)
Mercury played a sick joke with this pairing. I will say with the factory tune my 600SCIs fell on their face below 3,000 rpm, found out it was programmed in to keep the drives alive. Our previous stock 525/XR boat pulled harder getting on plane.