MarineEngine.com does not offer troubleshooting assistance or repair advice by email or by telephone.
You are invited to join our public Boat Repair Forum to seek assistance from other members.
You may also visit the Boat Motor Manuals section of our site to obtain a service manual.
I believe the 60hp is 4500-5500 rpms and you size the prop according to WOT rpms. With a light load in the boat you should be around 5500rpms. That boat looks like it has alot of weight up front try different trim angles and loading the boat different you will find the best combination and check WOT rpms. Figure 200 rpms for every inch of pitch. Say you have a 14 inch pitch and your engine only gets 5000 rpms max try a prop with 12 inch pitch will bring it closer to 5500 rpms. The 60hp is basically a detuned 70hp the WOT range for the 70hp is 5000-6000rpms. What is the WOT rpms your getting now and what is the size and pitch of your prop?