Weber Carb Mounting

nickknox

Well-Known Forum User
I’ve changed my inlet/outlet gasket and just need a bit of advice on mounting the Weber’s back to the inlet manifolds.
I’m going to change the Marib rings and the bobbins and caps. Where the best place to get these from?

I understand the carbs should be tightened so there is a 1 mm gap between the caps encasing the rubber bobbins. Is this correct?

When I took the carbs off there was a washer also between the caps so it went cap/washer/bobbin/cap. This looks to me as if someone put it together wrong at sometime. Also the caps were almost touching. I’m guessing this had the effect of the carbs being to tight to the engine causing vibration.

Thanks in advance for any advice
 

jonbills

Membership Secretary
Site Administrator
I’ve changed my inlet/outlet gasket and just need a bit of advice on mounting the Weber’s back to the inlet manifolds.
I’m going to change the Marib rings and the bobbins and caps. Where the best place to get these from?
Misab?
Eurocarb will have everything.

https://www.dellorto.co.uk/product-...d-fittings/manifold-accessories-and-fittings/
I understand the carbs should be tightened so there is a 1 mm gap between the caps encasing the rubber bobbins. Is this correct?
sounds about right.

When I took the carbs off there was a washer also between the caps so it went cap/washer/bobbin/cap. This looks to me as if someone put it together wrong at sometime. Also the caps were almost touching. I’m guessing this had the effect of the carbs being to tight to the engine causing vibration.

Thanks in advance for any advice
yes, there shouldn't be a washer in there. I think someone got it wrong before. L6 doesn't have a lot of vibration to worry about, but still best to not mount them solid.
 

nickknox

Well-Known Forum User
Got everything back on but she won’t fire up. I know that wasn’t the problem I just like things to be correct. She had ran for the 10 years I’ve had her mounted like that.

I changed the inlet/outlet manifold gasket because I could see it blowing badly but she hasn’t started since

I’ll keep tinkering and trying. She’s always a temperamental bitch if she hasn’t been ran for a while and it’s well over a year since she was running
 

Rob Gaskin

Treasurer
Staff member
Site Administrator
Got everything back on but she won’t fire up. I know that wasn’t the problem I just like things to be correct. She had ran for the 10 years I’ve had her mounted like that.

I changed the inlet/outlet manifold gasket because I could see it blowing badly but she hasn’t started since

I’ll keep tinkering and trying. She’s always a temperamental bitch if she hasn’t been ran for a while and it’s well over a year since she was running

Use 'Easy Start'.
 

nickknox

Well-Known Forum User
Ok update
Tried starting with brake cleaner but no joy.
Removed and cleaned plugs
Checked distributor cap and inside scored to f**k.
Had a spare old cap and she fired up. Coughing and spluttering a lot
Need to buy a new dizzy cap and rotor arm if any can help
 

jonbills

Membership Secretary
Site Administrator
Ok update
Tried starting with brake cleaner but no joy.
Removed and cleaned plugs
Checked distributor cap and inside scored to f**k.
Had a spare old cap and she fired up. Coughing and spluttering a lot
Need to buy a new dizzy cap and rotor arm if any can help
that's good news. you can probably get a cap and rotor delivered from Rockauto before next weekend.
 

nickknox

Well-Known Forum User
After watching YouTube videos I’m an expert at balancing Weber’s. I don’t appear to have “air bleed screws” did they have them on all models?
I think she’s over feeling. The plugs are wet and she over runs.
 

nickknox

Well-Known Forum User
Suggestions welcome on servicing Webers. Is this something to be tackled or left to experts?
 

jonbills

Membership Secretary
Site Administrator
I don't think they all had air bleeds, although I'm more familiar with Dellortos, so will defer to others on that. Overrunning is not really to do with the carbs - while the engine is turning over and sucking air, it will draw fuel from the carbs. Turning the engine off cuts the power to the coil and so stops the sparkplugs. If it continues to run, it's because the fuel is igniting through some other means - probably something like carbon build up glowing red hot.
Are the plugs wet after just idling? a Colourtune is invaluable in adjusting idle mixture.
 

Albrecht

Well-Known Forum User
After watching YouTube videos I’m an expert at balancing Weber’s. I don’t appear to have “air bleed screws” did they have them on all models?

I might be able to give a few pointers. I grew up with Weber DCOEs in the family (Dad's side of the family, not mum's...).

What series are they?
 

Albrecht

Well-Known Forum User

OK, that's good, as they are the 40DCOE series type which Weber themselves recommended for these engines (along with the 45DCOE-9). However, by definition they will be old...

To make sure we are talking about the same thing, what exactly on the carb bodies are you calling "air bleed screws"? You should have 6 idle mixture control screws (one for each venturi) which screw into the body of the carburettor near the manifold. They have springs around them to keep them from self-adjusting. Are they present and correct? If not there, you won't have any chance of setting a stable idle speed/mixture.
 

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nickknox

Well-Known Forum User
I wanted to get a "default setting" for the carbs and watched a youtube video. It may have been a newer Weber. It had Air Bleed Screws (with a locknut) near the Idle Mixture Screw.
My Idle mixture screws are there.
His settings were (It was a Pinto)
Idle Mixture Screws 1 1/4 turn
Air Bleed Screws fully closed
Idle speed screw half a turn after touching
 

nickknox

Well-Known Forum User
I’m going to get a service kit for my Weber’s from Eurocarbs.
I’m guessing I’ll need the 150 fuel valves or should I strip the carbs first and check.
Any advice on cleaning the carbs. My guess is ultrasonic cleaner. I could do with one for the workshop. Any suggestions?


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nickknox

Well-Known Forum User
499a9f31bb248f5cf2f6725b2104fcd1.jpg



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nickknox

Well-Known Forum User
79f6f9c0e1bb23958b2aac7821e56d68.jpg

Okay I’m mid strip and the fuel valve I’ve order and received is 150. The one I’ve took out is 175
What difference will it make?
Do I need to order 174’s?


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