I think the carb is the same as an 8N and it's about as easy and basic as it can get. (Easier than unrolling, cleaning and oiling that sorry air cleaner mesh IMO 
) One thing different----turning the idle screw in ENRICHES the idle mixture. Initial setting is approximately 1 turn open from seated position. Then with engine idling, turn screw in until idles becomes rough then back out until smooth. Main jet is one turn open for start, then adjust further for smooth running at high RPM.
When I bought my 8N a few months ago I had your exact same symptom, it would run rough or not at all unless it had a lot of choke, hot or cold. I pulled and went through the carb but it was in perfect shape. I ended up pulling the distributor, replaced points and condenser, dis-assembled and freed up the gummed up centrifugal dist. advance. After the distributor work it runs perfectly. The points didn't look all that bad, but I remember from WAY back, a bad condenser can show the same symptoms as a starving for fuel situation. You might want to check that out if the carb work doesn't get it. FYI the float level is 1/4" for an 8N, don't know if yours would be the same.
On Edit: I just found some great carb information here from a thread like yours,
) One thing different----turning the idle screw in ENRICHES the idle mixture. Initial setting is approximately 1 turn open from seated position. Then with engine idling, turn screw in until idles becomes rough then back out until smooth. Main jet is one turn open for start, then adjust further for smooth running at high RPM.When I bought my 8N a few months ago I had your exact same symptom, it would run rough or not at all unless it had a lot of choke, hot or cold. I pulled and went through the carb but it was in perfect shape. I ended up pulling the distributor, replaced points and condenser, dis-assembled and freed up the gummed up centrifugal dist. advance. After the distributor work it runs perfectly. The points didn't look all that bad, but I remember from WAY back, a bad condenser can show the same symptoms as a starving for fuel situation. You might want to check that out if the carb work doesn't get it. FYI the float level is 1/4" for an 8N, don't know if yours would be the same.
On Edit: I just found some great carb information here from a thread like yours,
