7 replies to this topic

[pinkmini99]

Right guys and girls I've just fitted a 1310 with a 276 cam stage 3 head lightened flywheel and back plate with a Webber DCOE 40 carb I've got to start and run but it revs to high I'm thinking it the jets it has got in it at the moment
The ones have
150
F11
180
On it


The others have

50F6

On them

What I would like to getting running nice so I can get it to a rolling road

[Stiggytoo]

Adjust the idle screw?

[pinkmini99]

Adjust the idle screw?

Tryed all possible things with the idle screws

[jeffm5150]

Your 40DCOE should have no problem idling at 1000 RPM or even lower, although your 276 cam might not allow the engine to idle smoothly at that speed.  Follow the Weber instructions on setting up the idle - set the idle speed to around 800-900 first, then set "best lean idle" mixture.  Once the idle mixture is set reduce the idle speed to where you want it.  You'll be chasing your tail if you've set the idle speed too high using the idle speed adjuster screw.  Doing so will cause the dreaded "DCOE flat spot" just off idle (since the progression ports are being used to set the idle mixture) and it will be a bear to correct.

 

If you're having trouble reducing the idle speed even with backing the idle speed screw all the way out, check to make sure the throttle linkage is not binding and make sure the throttle plates will fully close at idle (they should be [virtually] fully closed at idle).  You might want to disconnect the throttle pedal linkage and make sure it's not the thing responsible for fast idle.  From what I've seen and read, you should be able to remove the progression port plug(s) and confirm that the throttle plate is covering the first progression hole.  If it's not (meaning the throttle plates are open enough to no longer cover the first progression hole), pull the carb off and find out why the throttle plates are not fully closing.  Maybe you've got a bent throttle plate shaft, or there's another idle speed screw that you didn't see (mine has one on the carb and one on the linkage).

 

Here's a good reference for DCOE carbs which goes into detail all of the things you're going to need to understand to get your engine running even remotely decent.

 

Hope it helps.  I've spent the last few weeks street tuning a 45DCOE on my A-series 1275 block.  It's not easy but the payoff is worth the effort.

[Dusky]

Your 40DCOE should have no problem idling at 1000 RPM or even lower, although your 276 cam might not allow the engine to idle smoothly at that speed.  Follow the Weber instructions on setting up the idle - set the idle speed to around 800-900 first, then set "best lean idle" mixture.  Once the idle mixture is set reduce the idle speed to where you want it.  You'll be chasing your tail if you've set the idle speed too high using the idle speed adjuster screw.  Doing so will cause the dreaded "DCOE flat spot" just off idle (since the progression ports are being used to set the idle mixture) and it will be a bear to correct.

 

If you're having trouble reducing the idle speed even with backing the idle speed screw all the way out, check to make sure the throttle linkage is not binding and make sure the throttle plates will fully close at idle (they should be [virtually] fully closed at idle).  You might want to disconnect the throttle pedal linkage and make sure it's not the thing responsible for fast idle.  From what I've seen and read, you should be able to remove the progression port plug(s) and confirm that the throttle plate is covering the first progression hole.  If it's not (meaning the throttle plates are open enough to no longer cover the first progression hole), pull the carb off and find out why the throttle plates are not fully closing.  Maybe you've got a bent throttle plate shaft, or there's another idle speed screw that you didn't see (mine has one on the carb and one on the linkage).

 

Here's a good reference for DCOE carbs which goes into detail all of the things you're going to need to understand to get your engine running even remotely decent.

 

Hope it helps.  I've spent the last few weeks street tuning a 45DCOE on my A-series 1275 block.  It's not easy but the payoff is worth the effort.

Faq worthy imo.

[pinkmini99]

Hi I think it a combination of things now but mainly the throttle linkage or should I say the old linkage that was left on the carb when I brought it 😑 so off to mini spares to hopefully sort out a new one

[pogie]

Double check your linkage is letting the butterflys close all the way.  I've got Webers own LP2000 linkage on my DCOE and found it was holding the throttle open even with the idle screws removed.  I took some material off the throttle stop on the linkage with a file and the engine behaved itself right away.  

[pinkmini99]

Thanks guy it's all sorted now I hope