68F100 Fuel-up Log

1968 Ford F-100
Property of F100Truk. Added Aug 11 2017

Showing a single fuel-up

Nov 7 2017

So today before I even ran the engine for the day, I tightened the valve cover bolts just a little more as they needed a little more. Then I discovered that the brass nipple into the carburetor that controls the vacuum advance was quite loose. I took it out, cleaned the threads and re-seated it in the carburetor. There's a rubber grommet inside the fitting to seal it and might not be compatible with the nipple itself as it sticks out a little too much for a perfect fit. Nevertheless I tightened the nipple back in to make sure it seals correctly. I did not use white Teflon tape to seal as I'd rather do without it, so I will need to keep an eye on it. Regardless, this definitely could have an impact on the cold engine misfire. It probably caused a vacuum leak that was more noticeable on acceleration as vacuum increases under that condition. The leak probably caused a lean condition in the carburetor AND an incorrect advance setting until such time the carburetor heated up, expanding and sealing the nipple which explains why the misfire would only happen when the carburetor was cold. We will see, but I feel very optimistic. The only thing that could create a problem is the incorrect nipple length for the rubber grommet. I also checked the ignition timing and it is correctly set at 6 BTD.

Added by F100Truk on Nov 7 2017 at 1:23 pm