Today I took my longest all at one time trip in the 26 (50 miles) and the only thing I had a problem with was the choke knob keeps turning as I drive and it makes the car run rich or lean till I notice it running different and turn it back. I have some ideas of how to fix this but wanted to know how others have fixed this little problem. Other than that it was a real nice drive. I even took the worst hill around this area in high gear and just made it to the top without down shifting.
Tighten the mixture clamp nut.
Bob, if the carb is a Holly NH I think you must be referring to the mixture needle which has a jamb nut that can be tightened to keep the mixture set. I always turn the mixture about a quarter turn out(counter clockwise) to start a cold engine then lean it out as the engine warms up. The trick is to get the jamb nut snug but not too tight. If I've missed the boat on this some one jump in & belp BOb
Edward R. Levy
P.S. Like humans no two T s are the same so you will soon learn where your motor starts & runs best. I hope this helps
Edward R. Levy
Also use the anti-rattle rubber donut in the dash to help keep it from turning with out tightening the carb too tight.
When you tighten it, make sure it is still loose enough to make changes. For instance, you might want it richer when you start and then lean it out as you go. If you tighten it too much, you will not be able to do that. Also, be careful as the needle which goes through the center of the nut is pretty fragile. It has a very sharp point and if that point is turned down too far into the carb it will be ruined and then your mixture will really be messed up. As you tighten the nut, make sure you are not moving the needle down too far and endangering that point. The nut is shown here in green, the needle in red.
One thing I do to keep the fuel mixture rod from turning while driving is once I find the "sweet spot" setting for the carb I re-adjust the choke rod so the "tang" is at the 6 o'clock position. Along with the a rubber grommet in the dash this works pretty well in my 26's.
I'm not sure how it is on other years, but on my two (2) 1926 Model T's, the choke rod goes from the carb to the dash hole by passing through a hole in the firewall. I remedied this problem by slightly bending the choke rod between the firewall hole and the dash hole, which served to put constant tension on the rod at the dash hole, making it less likely to turn, by itself, from the vibration. Jim
I had this problem and the cause was that my choke rod was slightly bent. When I straightened it out I no longer had the problem.
I went to the hardware store and found two rubber grommets - a smaller one for the hole in the dash and a larger one for the hole in the firewall. That made the rod too tight and it tended to pull the grommets out. A little bit of silicone grease on the choke rod and the grommets, and now everything works smoothly and stays adjusted. It also allowed for a looser adjustment on the clamp nut, and the whole assembly works better.
I will check the nut and also had thought about some sort of grommet in the hole on the dash to stop the noise from there. I have started this car at temps down to +7F so it does need to be turned when cold and then turn it back some as it warms up. I have found that sweet spot at about 6 O clock but it takes a while to get there this time of year so it was at about 3 O clock for part of my trip and that was where it wanted to move on me the most. On the way home it stayed in place so I know it wont take much to keep it there and will open the needle a few turns to be safe before I turn the nut and then turn it back when I am done.
We got around 8 inches of snow over night and now the wind is blowing it around so it may be a few days before the next road trip but I might play in the yard some more with it.