Weber 40 DCOE problems

[apgodden]

I am at my almost at the stage to ripped off my weber DCOE 40'sand sell them and go to bike carbs....

I have a 2.0 pinto slightly bored out fast road cam and ported head.

32mm Choke

F16 Emulsion tubes

145 Main jet

180 Air corrector

45F9 idle jet

Malpasi fuel regulator set at 3.5 psi

 

I had a old school mechanic look at it yesterday and he dialled in the cam shaft. He got it running better than I could but it still will not tick over unless at 2,500rmp

The idle mixture adjustment has little affect.

If we cover part of the air inlets the revs increases

Dose this mean my main jets are too small?

[Jez Morton]

I doubt I'll be able to find the carb set up from my old car,  twin 40s fr32 cam. But I can say a rolling road session is probably the only way to get them setup and running properly. 

[apgodden]

Problem is I need to get it good enough to drive to rolling road.

[alantoon]

I was  given a base retting for twin 40s a while ago but I never got round to using it.If it is any good it was as below

32  chokes

F11 emulsion tubes

136 mains

180 air 

55f9   idle         

trouble is if you ask 10 different people what they are running you will get 10 different answers.

[blue]

Ok deep breath. 
forget the mains for a while. 
the revs are going up because your increasing the air speed 

it’s hard without seeing the car.  
so does the car stall below 2500 or does it not start ?  Unless throttle is applied 

are the carbs loosely bolted to manifold to stop fuel frothing 

can you be a little more specific on what the engine does if below 2500rpm.  

[apgodden]

Car will only start if the throttle is applied.

carbs are bolted tight against the plastic spacers / O rings.

under 2500 rpm it will stall straight away.

[kevin the chicken]

Carbs shouldn't be bolted too tight, there should be some rubber spacers between manifold and carbs to stop vibrations transferring across and making fuel froth up. The have a specific name which escapes me at the moment. They were the first thing that my mechanic checked. If it won't start without throttle then surely there is a blockage on the idle circuit or the idle jets are too small. A properly set up pair of Weber's work well and sound awesome 

[apgodden]

I have the Burton manifold with plastic spacers.  Everyone is saying air leak so tightened them up....

 

also I have been told that the accuspark distributor and plugs are not good has anyone else had issues

[Davo]

I’ll be interested in this. I have a dgv and get a similar issue. I know where the idle port is on the carb and am convinced it only runs once the progression ports are exposed, never with just the idle circuit. Convinced, there was a blockage, I’ve taken it off, drenched it in carb cleaner, blown air through it etc etc. 

[Bob Tucker]

Thackeray washers. Like a 2 coil spiral, There must be a gap (size not important) between the coils. It should be possible to move the carbs up & down slightly.

[kevin the chicken]

Yeah I googled it after I posted. The thackeray washers are about 99p each! My mechanic didn't look at me gap he just tried to move the carbs. One of my carbs has a slight blockage in the idle circuit so that it doesn't idle very smoothly but can't shift it with an airline so left it alone 

[blue]

I had nothing but problems with there spark plugs.  -miss fires -uneven idle etc.  Found some new old stock Ford ones the difference was night and day. 
 

I think you need to balance the two carbs first. - do you know if your old school mechanic used an air flow meter when he was having a play ?  

Even if your idle jets are to small it should still idle even if badly 

I think you need a base set up 

so loosen up the balance lever between the carbs.  Tighten the screw so the lever JUST starts to open then undo it at the point just before it moves. 
this is not by any means accurate but you need a starting point 

mixture screws should be about 2.5 turns out from full in - mixture  screws just touch the base point NEVER tighten them in the carb 

for now close (screw in ) the air bypass screws -if your carbs has them again just so they close -not tight. 
 

as for air leaks spray some brake cleaner etc around the manifold joins -not into the carb mouth while car is running if you hear a difference in engine running you have a leak 

let me know how you get on.  

Edited January 31, 2021 by blue

[Bob Tucker]

NGK spark plugs have been the best for me in the redtop. We also use the exact same plugs in the Corvette with no problems at all. They get a really hard thrashing, but they dont do much mileage. Ive had brand new (Halfords) champion plugs fail immediately.

[Foz]

Hi Tony,

I'm guessing that you didn't get the settings I sent over in November.

For road use my DCOE40s have got 32mm chokes, 130 main jets, 50f8 idle jets. F16 emulsion tubes and 185 air correctors.       With these settings it pulls nicely from low revs all the way to 6000rpm.  (2.0 pinto, skimmed & ported head, FR32 camshaft).

Steve.