I just bought a 1998 Ranger R91 with a 200 Merc EFI and a 6" jack plate. Took it to the lake for the first time today to test it out. The motor seems to run fine but when I accelerate it won't go but about 5-10 miles per hour or less at full throttle. Sometimes it does this with the nose of the boat pointed straight up in the air. If I stop and let it set and take off again it may or may not take off right. it was hit and miss as to whether it would take off or lug down. Also the top end wasn't what I expected it to be. The previous owner told me it would run right at 80 but the best I could get on GPS was 56 at 5000 RPM. Does anyone have any suggestions as to what I'm doing wrong or what might cause this? I know something isnt right because I could run circles around this thing with my old boat which was an 18' Xpress with an 85hp Yamaha.
You need to do some basic checks on fuel and ignition system to see if they are working correctly..