In the manual for my 70 240z, it says to not depress or pump the accelorator pedal when starting when starting cold or warm, that the SU carbs are preset to assure correct mixture. In the manual for my 74 260z, for warm starting it says to depress the accelorator fully and hold it while cranking. Is this difference in procedure different because of the flat top vs domed top carbs or was it from learning more about how they were working in real life situations? Anyone with a 71,72, or 73 manual...are their instructions the same as the 70 or 74? If the carbs are described as pre-set for both models, why does the
260 later state to hold the pedal down? Seems like a contradiction.
Well pumping it does absolutely nothing as they don't have accelerator pumps..
The way I've found these crank the easiest cold is: pull the choke fully on, floor the accelerator and crank for about 2-3 seconds then release the accelerator. If it doesn't pop off when you back off the gas, floor it again for a couple of seconds and then let off again. This pulls more fuel into the engine when the pedal is floored and when you back off it shuts off the air, the engine goes rich and it fires off. They will crank just pulling the choke, it just takes a lot longer. Once it fires off, turn down the choke until it will just stay running as these cars foul plugs real easy.
Hot you shouldn't have to do anything (don't choke it!!!) except maybe give the accelerator pedal just a touch. Remember it's really an air pedal, not a gas pedal. Of course if it doesn't want to fire and it seems flooded, floor the accelerator while cranking.
Each car seem to be a little different in the way it likes to be cranked and it all depends on how it's set up. It should need to be choked to start cold, if it doesn't it's too rich. If you have to choke it hot, it's too lean.
One other "trick" that makes these run a bunch better is to swap in a 79-82
280ZX distributor. It's simple to wire these up (2 wires go from the dist to the coil), you remove all the balast resistor BS, it gives them great spark and the tach still works, unlike many aftermarket ignitions..
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