Need advise: I've been pushing a lot of snow this winter, and my 1950 8N has performed beautifully until today. She starts good and the engine runs smooth from idle to wide-open without the clutch engaged. When I put her into any gear and let out the clutch she starts to sputter and doesn't come out of it. Seems to sputter less with lower RPM's.
Fairly recently rebuilt carb, new gas, clean sentiment bowl, new spark plugs. I haven't noticed any black smoke from the exhaust. Any thoughts on my first line of attack?