I recently purchased an 2000 Wellcraft with Johnson 115 with low hours. The first time I put it in the water it would run fine up to the high 3000s. At rpms from about 3900 up it would continuously bog and surge. Sounded like it was not getting fuel, like when a tank starts going empty. When I got it home, I removed the fuel filter and cleaned it, and there was some trash in it so I thought that was probably it. Yesterday I took it back out and it did the same thing.<br /><br />Today I checked all lines for kinks, then disconnected the fuel line and blew it out with air from the tank back to the motor, then from the fuel filter back to the boat. Blew out the bulb at low pressure. Removed and inspected shutoff valve on tank and blew out the drop tube into the tank. I placed the ends of the hoses where I could see anything that came out and they all appeared clear and I didn't find any trash discharged. I'm afraid that I didn't accomplish anything.<br /><br />My question is, am I barking up the wrong tree? Could this be a timing problem? A carb problem? Motor idles great, responds to throttle great, just will not run smooth at higher rpms.