Hi there

Is anyone with a weber on here actually using the cold start device on their weber?
I am interested in what size starter jets you are using. My wife struggles with the current cold start procedure of 5 pumps and then light throttle crank to fire. Which works fine but I would like it to start nicely using the choke knob.
I currently have 65F5 jets in a 45 DCOE on a pretty stock 1275 and these are not big enough. I almost get a stumble with full choke but nowhere near a fire up. If I use the choke it does however decrease the amount of pedal pumps required so it is doing something. I was thinking I need about 90F5 and have ordered some tiny drill bits, but don't want to go too far as the starter jets are expensive. Just after a baseline.

cheers
Rick

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1310 SC 1969 Morris Deluxe - 15psi boost
1293 1968 Morris Deluxe Miglia - 45 Weber
HSV Maloo Z Series - Comp Cam - 300rwkw
Ford DF LTD - 5Ltr

When you say starter jets, are you referring to the idle jets?

I had to blank off my choke/starting device as it was leaking fuel due to the manifold angle.

This is my jetting, based on David Vizard’s How to modify your mini book. Running a 1275 with LCB extractors and a 45 DCOE, not sure if the cam but think it’s stock.

36mm choke
150 main jet
180 air corrector
F2 emulsion tube
40 pump jet
50F2 idle
4.5 aux Venturi

Cold start is fine, couple of pumps and it fires up. Have to give it a little accelerator due to the lack of choke till it warms up a bit.

My idle mixture needs a bit of fine tuning though as it’s running a little rich.


Sent from my iPhone using Tapatalk

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67 Van, 1275cc

I use the starter circuit/choke on my Dellorto. I don’t need any pumps or throttle to get it to start and idle. It does make it really rich, if you sit and idle it for a minute or so it’ll foul the plugs, so I normally start driving soon after starting

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Hi Timmy

Ok, cool. That's the outcome that I am after, don't suppose you know the size of the starter jets you have?

Cheers
Rick

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1310 SC 1969 Morris Deluxe - 15psi boost
1293 1968 Morris Deluxe Miglia - 45 Weber
HSV Maloo Z Series - Comp Cam - 300rwkw
Ford DF LTD - 5Ltr

Hi Gambo

No, I mean the actual cold start circuit jets, not the idle jets.
I have my 45 DCOE tuned perfect with jetting quite a bit leaner than you, but I am in a warm climate at sea level.
My AFR = Idle 14:1, Cruise:13.5:1, WOT/ full load: 12.5:1

I get exactly the same fuel economy as the HIF6/44 SU that was on the car for run in of this engine, and no dreaded 'Untunable lean bog' that so many people warned me of.

My jetting:

Italian 45 DCOE 13
34mm choke
145 main jet
190 air corrector
F16 emulsion tube
30 pump jet
40F8 idle
5 aux Venturi
60F5 Cold Start jet
No dashpot oil!

1293 stock cam, LCB's Maniflow 1 & 7/8 twin box system.

These carbs are great. I was previously an SU man but no longer (sorry purists).

So, as you can see my setup in idle and pump jets is substantially leaner than yours, so it makes sense that yours would cold start much easier. My wife forgets that she has to pump the pedal 5+ times and gets the shits that it wont start. The cold start mech with the right jets should solve this.

Cheers for the input

Rick

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1310 SC 1969 Morris Deluxe - 15psi boost
1293 1968 Morris Deluxe Miglia - 45 Weber
HSV Maloo Z Series - Comp Cam - 300rwkw
Ford DF LTD - 5Ltr

Hi Rick,

I haven't played with webers for a long time. Below are the jets in the two webers I have and have used on my previous Cooper S's. Hopefully, its of some use and doesn't muddy the water any further. I will be using weber #2 on my Mk 2 currently under restoration, suitably reconditioned and re-jetted to suit the new motor.

Your jetting:
Italian 45 DCOE 13
34mm choke
145 main jet
190 air corrector
F16 emulsion tube
30 pump jet
40F8 idle
5 aux Venturi
60F5 Cold Start jet

My carbs:
From what I can remember , both seemed very good on their respected engines - no flat spots. It worked particularly well with the 649, nice grey exhaust pipe.


Weber #2 - Last used 1983 : 1310, period 35/75 cam & later a 649, lcb-1 7/8" single muffler, good head, balanced etc

Italian 45 DCOE 13
34mm choke
130 main jet
175 air corrector
F2 emulsion tube
50 pump jet
50F9 idle
4.5 aux Venturi
50F9 Cold Start jet

Weber #1 - Last used 1980 : 1310, period 30/70 cam , sonic long 3-1 ,1 7/8" single muffler, mild head, balanced. Unfortunately, it has a broken flange when a mechanic tried to over tighten a bolt on the inlet manifold - hence weber #2

Italian 45 DCOE 13
34mm choke
145 main jet
180 air corrector
F15 emulsion tube
50 pump jet
45F9 idle
4.5 aux Venturi
60F5 Cold Start jet

For what its worth, I've never used a choke on any of my webered cars, ranging from the Minis to a Alfetta Gt and my Dino. Just a couple of pumps and start with a bit of throttle as others have previously said.

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1970 Mk2 Cooper S under restoration

Thanks ausdino. Those starter jets are also small. I will just have to start drilling mine out and see how i go.

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1310 SC 1969 Morris Deluxe - 15psi boost
1293 1968 Morris Deluxe Miglia - 45 Weber
HSV Maloo Z Series - Comp Cam - 300rwkw
Ford DF LTD - 5Ltr