Today I was helping a friend with a problem on his '10 T. When cold the car starts right up with one pull of the crank if you first give it two pulls on the crank with full choke and open the mixture adjustment an extra turn before you turn on the switch. Once started and after the mixture adjustment is closed a turn the car runs fine with good power and no hesitation. The problem is that after it warms up fully it just won't start. The engine was recently rebuilt and is still a bit tight but no matter what I tried to do it would not start with the crank when hot. I did feel as if it was harder to crank when hot than when it was started cold but not so hard that I couldn't pull it through. All the coils are buzzing in turn and the timing is set correctly. First I tried to start it without doing anything other than opening the throttle about 4 notches. When that didn't work I tried choking it with no success and then I adjusted the mixture to richen it but to no avail. Oddly, when we pushed the car down a slight hill it finally started up and again ran fine with no issues until we tried to start it when hot again after putting it back in the garage. I should mention that the owner has one of those reproduction NH carburetors from Cafins on the car which he recently installed but he couldn't say whether the problem started right after he made the change. Any suggestions?
The float level is very important. I have one which would start right up when cold without choking it, but when it was hot, it was flooded. I lowered the float level and now it needs to be choked when cold but starts right up when hot.
Anyway, that is something to check.
The valves may be too tight.