running rough

Tue Jun 01, 2004 5:09 pm

After rebuilding the carb last spring my cub has been running fine until a few weeks ago. It would start easy but would run rough when reved-up. It had a leaky petcock and often was low on fuel. I though maybe since it was drinking the dregs from the tank some trash got into the system. The old petcock didn't have a screen filter. Anyway I ordered a new petcock and while I was waiting on it I tuned up the electrical system with the parts I bought last year- points, condenser, rotor button and cap, plugs and wires. Afterwards it still would start easily but ran rough. When the petcock finally came I installed it and cleaned the main carb jet. I also discovered the air cleaner was dry because of a pin hole leak. Fixed that and filled it with oil per the manual. Now It is hard to start and runs even worse. I think it is running rich as I see whiffs of white smoke from the stack and it floods easily when starting. I have checked the float setting with H. L. Chavins clear tubing method and it is fine. I have tinkered with the carb setting with no success. I am thinking I need to disassemble the carb and clean it out. Am I on the right track?

Tue Jun 01, 2004 5:27 pm

White smoke usually means water. I'd do a compression check of all cylinders or remove the radiator cap and look for bubbles in the water. Could be a bad head gasket.