Hi, I've got an 85 Blue Fin with an 85 Johnson 90 vro. The boat was running well, but recently, when I was running across the lake at about 7/8 throttle, the motor cut back like it wasn't getting enough fuel. I pulled the throttle back to idle and let the engine catch up and brought it up to speed only for this to keep repeating. I took it out another day and it acted like this again but then straightend out and had plenty of power for the rest of the day. The next time I took it out it ran fine for the first hour then wouldnt hardly even get on plane, then with the throttle about half way would surge up and down like it wanted to go but just couldnt. The next day it ran fine. My throttle linkage seems stiff as well. I havn't had the boat very long. A recent compression test showed the top 2 cylinders at 120-125, but the bottom 2 only 80-100. I will pull the heads this winter and hopefully only have to do piston and rings. I'm just wondering if this is a pump issue, another fuel issue, a spark issue, or something else i haven't even thought of. Any input on possible causes would be a help in diagnosing this problem.
