Starting cold

[Boobouna]

Hi all,

My CS (original zeniths all stock no mods) normally takes 3-5 cranks before is starts up on a cold start after sitting for a week. I only drive it once a week. Is this normal?
It starts first go after the initial start during the day of driving.
I pump the throttle before starting the first crank as per the instructions to get the choke activated.



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[Simufly]

Not sure about carb engines perhaps the fuel is draining back through the fuel pump. Look on the bright side though, it gets the oil circulating before starting!

 

[deQuincey]

i use stock zeniths too
no matter one two or three weeks
always at first crank

i do have a non-return fuel valve and a fuel filter too before the mech fuel pump

procedure:
1- small touch with the tip of your foot at accel (listen to the butterflies as they will close then, if you are good you will differentiate two cliks as they are two butterflies)
2- deep push to the accel to "inject" the gasoline that is in the accel pumps
3- no feet
4- crank the starter

a tip for an ulterior start of the engine with warm engine, do not touch the accel pedal, never, before cranking the starter

 

[Boobouna]

So you need to push the accelerator a second time? I didn’t know that, I thought it was one touch on cold start.
Yes agree I never touch accelerator when engine is warm. Starts first time.


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[Boobouna]

i use stock zeniths too
no matter one two or three weeks
always at first crank

i do have a non-return fuel valve and a fuel filter too before the mech fuel pump

procedure:
1- small touch with the tip of your foot at accel (listen to the butterflies as they will close then, if you are good you will differentiate two cliks as they are two butterflies)
2- deep push to the accel to "inject" the gasoline that is in the accel pumps
3- no feet
4- crank the starter

a tip for an ulterior start of the engine with warm engine, do not touch the accel pedal, never, before cranking the starter

My car is an auto so I followed the instructions from the manual, which says touch accelerator once only.

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[Philippe db]

Hi Guys,

Very recognisable. My Cs with rebuild Zenith's and non return fuel valve will start at first crank if I use it daily as soon as it stands for a longer periode of time it becomes impossible to predict what will happen. Most of the time she will need a little help from the accelerator pedal.

That being said I always found it difficult to understand the logic behind the choke mechanisme. Cold start will activate the choke and the rpm's will start climbing to warm up the engine. So far so good until, just after starting your cold engine, you touch the accelerator pedal and by doing that stop the choke function.

So to avoid this when leaving my garage with a cold engine and choke working I drive only by using the clutch until I reach the road. Once on the move everything is fine as long as I don't need to stop after a few meters.

 

[deQuincey]

So you need to push the accelerator a second time? I didn’t know that, I thought it was one touch on cold start.
Yes agree I never touch accelerator when engine is warm. Starts first time.


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the theory says one push, i find a second push very useful when the car has been sitting for more than a week, so i do this always
i shared this tip with friends that told me it has proven to be very effective, and no harm

That being said I always found it difficult to understand the logic behind the choke mechanisme. Cold start will activate the choke and the rpm's will start climbing to warm up the engine. So far so good until, just after starting your cold engine, you touch the accelerator pedal and by doing that stop the choke function.

So to avoid this when leaving my garage with a cold engine and choke working I drive only by using the clutch until I reach the road. Once on the move everything is fine as long as I don't need to stop after a few meters.

yo do well, otherwise you will iterrupt the choke function and it will be a sort of coitus interruptus that leads to an unhappy evening, your 1200 plus revs will be able to manage the car movement until you reach the outside world

it is all about a very delicate serrated element that engages and dissengages the choke , i assume that the guy that rebulit you zeniths worked in cleaning the mechanism and fixed the spring in position and set it to table settings for correct operation, from that point on is the bimetallic spring that operates the top closed butterflies opening them progressively as they warm up with the help of the electric solenoid, but meanwhile this happens the lower butterfly rests in choke position and you need a second kick to let it rest and stop climbing those revs without contention

zeniths are a marvel, the summit of carb engineering for comfort, safety, and performance, others may have one or two of those but ....