sasquitch007
Probationary User
Hello everyone, I am new to this site and to outboards. I bought a 1985 xst last year. It has a 220hp mercury converted to carbs (wh22s), 6" setback manual jack plate,and just added water scoops. I have been trying to get more or at least normal speed for this hull. When I bought the boat it had a 26p big ear chopper on it. The best numbers I got with it 3 1/2" below the pad were 62mph(GPS) at 6000rpm. I bought a 25p trophy and raised the motor to 2 1/2" below the pad and got 62mph @ 5800 rpm. With the motor at 2 1/12" below the pad ,the trophy would shoot a huge rooster tail if I tried to trim at all. I have now added the water scoops and put the chopper back on and raised the motor to 2" below the pad. I could not get a wot test because the chopper now has a bad vibration you can feel through the hull. The more rpms the worse the vibration. I have talked to other about the vibration and most say that the chopper is out of balance? I never felt any vibration when the chopper was at 3 1/2" below the pad. I have talked with others that have owned xst boats and all of them say with my motor I should be getting a lot better numbers. I don't really know what is the right direction to go. Do I need more setback, a nosecone? I have great water pressure, with the scoops, 25psi at wot. Should I raise the motor? When I ran the trophy the slip numbers did get better. I thought I might put the trophy back on and run it at 2" below the pad. I am just not sure how high you can run a trophy. I know if could not trim at 2 1/2" below. I pretty sure I want be able to trim at 2" without a rooster tail. I have also been told that a nosecone will not help me until I reach 80mph? I greatly appreciate any help. I know this is a long post with alot of questions. I just wanted to give as much information I could. Thanks again for any help. Brad