DCOE Idle jet query

**djmca** · 25-06-2021, 10:21

Hi All,

New to the Weber scene. Running DCOE 45s on my 2.0 Silvertop Zetec, these are the 5 hole Zetec specific carbs bought brand new outta the box. Supplied jetting as below, cars drives well actually, pulls well etc. Intend to RR it to setup properly but i have a miss down low on part throttle and trying to learn by sorting it myself. Going lean (AFR showing 15-16 on light acceleration) and car hesitating/missing.

After reading all setup/jeting guidance i have tried changing the idle jet, i am up to 60F9 and the lean spot is still there. Better, but the miss is still there. This size seems OTT?

I appreciate its hard to diagnose from a description of the symptoms but any help would be much appreciated

Engine is standard apart from 4 branch and exhaust.

Jetting is:-

36mm Venturi choke
4.5 Auxillary Venturi
145 Main jet
F16 Emulsion tube
155 Air corrector jet
40 Pump exhaust valve
55F8 Idle jet - currently 60F9
45 Pump jet
2.00 Needle valve.

**Miniliteman** · 26-06-2021, 10:00

Try 60F6. If during the RR setup you need a bigger main jet you can try 55F6.

**djmca** · 26-06-2021, 11:50

Is a 60F6 not very big?

**Miniliteman** · 26-06-2021, 18:30

It sounds big yes. But if the engine needs it so be it.
The modern type of Weber DCOE's (Spain) are not as well build as the old genuine Italian carbs.
If you have an old and a new type next to eachother you'll see what I mean.
The newer type seems to need a bigger idle jet than before.
The F6 idle jet has the smallest air hole of the range to keep the mixture richer from idle upt to transition rpm.

**djmca** · 26-06-2021, 20:57

Thanks

I have 69F12 and F6 jets sitting here so will give them a go, just thought they were far too big

**djmca** · 18-08-2021, 12:00

Update on this

Increased idle jet to 65F8 and miss is better but still there on light acceleration (afr jumping 13-15). Other issue is that on cruise its sitting around 10 on the AFR so too rich

**Miniliteman** · 18-08-2021, 16:27

Have you tried 60F6 as suggested?

**djmca** · 24-08-2021, 12:13

Sorry for late reply

Yes, have tried all through the jet range, right from 50s up to the present jet. Right through the F numbers too. Advanced the timing slightly across the 2.5-3k rev range that the miss was happening and it seems to have helped again

Have 165 air correctors ordered to try and solve the over fuel on cruise