Rebuilt 617 mosquito murderer conversion!

[Pete Burton]

I finally started up the rebuilt engine in my SD this weekend and it sounds great. Also, I murdered most of the mosquitos in my neighborhood with the smoke. The more I ran it, the less smoke and the better it ran, but after a good 15 minutes of idling, it still smokes a lot. Can old fuel, minor air entrapment or minor IP timing variance cause a great deal of smoke? It's really a lot, and the idle speed surges between about 800-1600 RPM. I know that some initial smoke can be expected, but this seems like a lot