Surging

After I run my '66 Spuer 12, it starts surging really bad. What could be the cause of this and how can I stop it.

Thanks
John
Chesapeake, Va

At low or high speed?

mine did the same thing. i ran some sea foam thru the head and sea foam deep creep thru the carb. runa a lot better now. this is what i did,do at your own risk. ran engine til it was hot,pulled the sparkplug and poured about 2 ounces in the head. when i quit smoking,i poured about another ounce in and slowly turned motor over to let it get everywhere around valves and piston. let it set about 20 mins,replaced plug and fired it back up. it will smoke like a train for a min. after it smooths out,spray deep creep into the carb a few times.this stuff cleans carbon buildup off great. also pour some in fuel tank for continous cleaning. like i said, do at your own risk.

The surging problem seems to be worse after the engine gets hot and at low speeds. The engine was completly re-built and only has a few hours on it. This problem just started. Could it be that the carb. isn't set right? I tired adjusting the adjustment under the the bowl. I probably got it screwed up. Do you know how many turns this adjustment shoud have?

Any help with this would be great.
Buzzard[b]

1 and 1/4 to 1 and a half is a good starting point.

On one of mine the surging turned out to be excessive play in the throttle shaft(worn out).
They suck air down by ,which causes the govenor to hunt.

Just a suggestion.