What else would make a '92 J10Rena run rich?

[ba_50]

This is a low time motor and has a new fuel pump. I checked it for leaks out the back and didn't find any but can try another tested pump when I get back. The carb has an upgraded plastic top, is clean and parts are ok. The motor idles great but won't power up. If leaned it picks up a little better. Both cylinders are firing and it has a new head gasket. Someone on iboats said the cam adjustment can help lean it out so I can try that. Any other ideas? Thanks.