"Starter Jets" Query - Another Dumb Question!

PostPost by: AlfaLofa » Fri Sep 05, 2014 1:42 pm

Could somebody tell me what the DCOE "Starter Jets" do?

Q1) Do they function only when the cold start/choke is used?

Q2) Do they have ANY function when the cold start/choke is not being used?

I ask because one of the "Starter Jet" channels in a DCOE I have appears to be blocked.

(I've tried ultrasonic kit - but to no avail)

A pipe cleaner can be inserted to a depth of about 93mm down the tube vacated by jet A.

However the pipe cleaner only reaches down 83mm in tube B.

If the answer to Q2 is "No" I will abandon my attempts to clear the blockage.

(Further inspection suggests that the lead plugs have been inserted too deeply into the channels of tube B - hence the blockage).
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PostPost by: Panda » Sat Sep 06, 2014 1:49 am

Hi
The starter jet system on a DCOE is almost like a separate carburettor. It's only function is to provide extra fuel and air to richen the mixture on cold starting. I have a pair of Italian 48mm DCOE's which came from the factory with no cold starting system at all. They were used on Formula Atlantic engines.
I have been working on Weber carbs. since 1967 and I can't remember a single instance of needing to use the cold start, even when in the snowfields. Mind you I haven't lived in Bonnie Scotland since 1955!
About the worst thing that can go wrong with the system is if the starter pistons don't fully close when not in use thus causing an over rich condition at idle which can be hard to diagnose. Usually one idle mixture screw has to be virtually closed to correct the idle
I personally give the accelerator 3 pumps slightly depress the pedal, then hit the starter and just blip the throttle to keep it going. Works for me every time.
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