Rebuilt my engine, new block, older manifold, rebuilt the carb. Started right up in the driveway, seemed ok. Ran it at the lake on the trailer on the ramp for about 20 minutes, all ok. Took her out on the lake, let her idle for about 5 minutes until warm, hit the throttle, took right off for 3-5 minutes, then died....picked up a bunch of junk in the carb. Pumped out the tank, added fresh fuel, switched carbs ( I Have another good one of the engine I bought), changed the fuel filter and she'll start right up, either at speed or at idle, but if started at idle, she'll die when accelerating...any ideas?