My 3.0 carb finally needed a rebuild this year after 25 years of good service. I looked at rebuild kits, but by the time I bought a kit, a float and choke(mine needed both replaced), then a can of carb dip, it wasn't a ton more to have a pro rebuild it. Flying Fish did mine. I mailed in off and got it back in about a week. I bolted it on, started it and adjusted the idle mix. It ran great.
http://www.marinecarburetor.com/index.html
The thing takes forever to start up cold./QUOTE]
Have you tried adjusting the choke?