Motor will not start through normal process. A (very) small shot of starting fluid makes it fire right up and run. After that it runs rough and rich, lot of smoke. Carb and lines full of small black particles, looks like fuel lines deteriorating? Removed carb, cleaned, replaced lines that were accessible, sprayed carb cleaner followed by compressed air through the remaing lines. I isolated the diaphram to keep from blowing it up. Cleaned and gapped plugs, reinstalled everything and problems remain. Neighbors boat, trying to help him out but now I'm at a loss. Plastic top on carb with idle adjustment as part of it. Fuel inlet strainer/pump and water pump recently replaced. New, clean fuel and new line from tank to motor. Any suggestions would be appreciated
