Weber DCOE series carb illustrated

Weber 40 45 DCOE

This carb is synonymous with performance and almost as good as fuel injection in its time. The carburettor is fully customisable with all the jets and venturi's able to be changed to suit whatever application you have in mind.

I found a DCOE Weber Instruction Manual that goes in deep. Deeper than I have ever gone as I did not have the special tools.

I found this helpful article from Redline Performance. A Recommended Jetting Guide for fitting Webers to popular old cars.

Setting float level is easily achieved. The carb top over and lay as shown the the diagram, allowing the float to rest on the spring loaded needle and seat without compressing the ball bearing on the needle. If the ball compresses, tilt the top clockwise until the ball is not compressed. Now set the float level to 5mm as per dimensions. This is with the gasket Gz in place.

Tang Lc is bent to achieve the float height. Ensure you don't accidentally twist the tang and also that the tang is tangent to the needle. If you cannot get it at a tangent then you may need to space the seat up or down by changing the thickness of the washers.

Tang A is bent to achieve the float drop. This is most important because if the float drop is more than specified the needle will jam in the seat barrel and cause major flooding.

These dimensions are for the round float only, not for the new plastic one (item 9) as in the schematic below.

Also be aware the instruction sheet you receive with the kit may differ in procedure and dimension. Use the dimensions given in the kit in this case.

Item No.	Description	Item No.	Description	Item No.	Description
1	Filter Cover	28	Locking Screw ( x 2 )	60	Pump Rod Spring
2	Filter Cover	31	Lock Washer ( x 2 )	61	Pump Rod
3	Filter Element	32	Throttle Shaft Nut ( x 2 )	62	Starter Jet ( x 2 )
4	Jet Inspection Cover	33	Throttle Plate ( x 2 )	63	Pump Valve Ball ( x 2 )
5	Screw (x 9)	35	Throttle Plate Screw ( x 4 )	64	Stuffing Ball ( x 2 )
6	Jet Inspection Cover Gasket	36	Cover Gasket	65	Retaining Screw ( x 2 )
7	Top Cover Gasket	39	Screw ( x 2 )	66	Needle Valve Gasket
8	Needle Valve	40	Screw ( x 2 )	67	Fuel Union Gasket
9	Float (plastic)	41	Pump Cover Gasket	68	Fuel Union
10	Emulsion Tube Holder ( x 2 )	42	Cold Start Unit	69	Fuel Union Gasket
11	Air Corrector Jet ( x 2 )	43	Pump Exhaust Valve	70	Fuel Union Bolt
12	Idle Jet Holder ( x 2 )	44	Idle Mixture Screw "O" ring ( x 2 )	71	Inspection Cover ( x 2 )
13	Emuslion Tube ( x 2 )	45	Throttle Lever	72	Float Pin
14	Stud	46	Cup Washer ( x 2 )	73	Cable Clamp
15	Main Jet ( x 2 )	47	Spring ( x 3 )	74	Starter Air Jet ( x 2 )
16	Idle Jet ( x 2 )	48	Vacuum Screw (x 2 )	75	Top Cover
17	Auxillary Venturi ( x 2 )	49	Pump Jet Gasket ( x 2 )	76	Plate
18	Air Horn (x 2 )	50	Spring	77	Washer ( x 2 )
19	Air Horn nut ( x 4 )	51	Spring Plate	78	Bearing ( x 2 )
20	Washer ( x 4 )	52	Throttle Stop Screw	79	"O" ring ( x 2 )
21	Air Horn Tab ( x 4 )	53	Pump Plunger	80	Inspection Cover
22	Main Venturi ( x 2 )	54	Starter Valve ( x 2 )	81	Gasket
23	Stud ( x 4 )	55	Starter Valve Spring ( x 2 )	82	Pin
24	Lock Washer ( x 2 )	56	Idle Mixture Screw ( x 2 )	83	Cover
25	Cap ( x 2 )	57	Pump Jet ( x 2 )	84	Pump Cam
26	Air Bypass Screw ( x 2 )	58	Pump Jet Oring ( x 2 )	85	Throttle Shaft
27	Lock Nut ( x 2 )	59	Pump Jet Cover ( x 2 )	86	Washer

Below is an alternate kit I used on a 40DCOE. On close examination you will see several differences between the schematic above and the one below as well as different float level specs. The most obvious is the aux venturi differences. I used the below procedure when I re-kitted this 40 DCOE. Please do not e-mail asking which one should be used. I would choose the lower setting and if it is found to be delivering fuel late, then raise the float level to the dimension on the top schematic.

I simply do not have the correct schematic of this 40DCOE that I put a kit through. I found some float level specs inside the DCOE Weber Instruction Manual (link to the manual at the top) and as luck would have it the spec for this Weber was 8.0mm with gasket on with a 15mm drop. The correct float level setting also depends on the angle the carby is fitted. Some are fitted flat while others may be at a 5-10 deg angle. These two cases would require different float level settings. As you can see in the table below that there are four different float level settings listed when these were fitted by factory. Each vehicle had differing specs. Confusing right, because DCOE's are fitted aftermarket, choosing a float level can be daunting. I would start at 8.5mm with a 13.5mm drop. If the main jet circuit starts late then raise the float level. It is not to difficult to take the top off and readjust. This is of course dependant on the correct choke & aux venturis being fitted as well as emulsion tubes. All of these contribute to fuel delivery at the correct time.

Doing a 45 DCOE re-kit at the moment

Soft mounts may also be required on a Weber aftermarket installation. I have included the fitting instructions below for the two most popular soft mount brands. It is very important that soft mounts are fitted correctly, if their too tight, then you may as well use normal base gaskets because the benefit provided to the installation will be zero. Too loose and they will leak vacuum. View the video below to get what I mean.