19-01-2018, 02:38 PM
(This post was last modified: 19-01-2018, 02:39 PM by Martin Prior.)
(19-01-2018, 01:59 PM)Nick Salmon Wrote: It is a feature of several of my 7s that, from cold and with the choke knob fully out, they will start very smartly, run cleanly for perhaps 5 seconds, and then die away and stop. Operating the throttle makes it die immediately. Wait a couple of seconds, start up again, same thing. This will happen three or four times and then, at last, they will continue to run happily and everything is normal. Other 7s with the same setup will start and run immediately.
I always manually pump fuel up to fill the float bowl prior to starting - which is what it initially runs on of course. All use 26VA Zenith carb.
Any clues as to why this happens? Is it a fuel pump issue?
Like you, Nick, I always prime the carb before starting from cold, and then usually turn the engine over three of four revolutions on the handle with the ignition off. The car then always starts on the first compression.
I only use full choke on my cars on very cold days. 75% choke is usually quite enough. If I do use full choke, the car behaves as you've described does unless I very rapidly push the knob back in by about a quarter as soon as the engine starts to run.