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PostPosted: Tue Jul 19, 2016 1:32 am 
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So I popped the top off of my Weber carb to try to investigate a low power and pop scenario. I simply unscrewed the Jets in the top center and base of the bowl for a quick shot of air. Beyond some debris in the base, nothing looked blocked.

The accelerator pump spring shot the little dime sized cap up, which was a royal pain to hold down. Is there a trick here?

After putting it back together, I found that top end power was incredibly stronger. I can hit almost 80 on a downhill and easy 75 on a slight incline.

The problem is slight throttle and idle. It likes to stall on deceleration now, and slight tip in creates a bogging scenario. Any advice on what to look at? I did not touch the idle screw.


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PostPosted: Tue Jul 19, 2016 6:13 am 
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Sounds like you moved a bit of dirt or something from one place to another!

Take the two screws at the very bottom of the carb out and give the holes a squirt of air. Make a note of how far they are out first. Line up the screwdriver slot with a point on the carb body. slowly wind the screw in counting how many turns it take for it to hit bottom. Take it all the way out and clean. Put it back it till it hits bottom and then wind it out the same number of turns as you noted down.

Just be careful how you make it hit bottom, as it is very easy to change the shape of the needle point which will give you erratic idle afterwards!

You might need to take the whole carb body off the manifold and dismantle / clean everything like that. I have a small ultrasonic bath cleaner and the carb just about fits in it with everything taken off. Makes a good job of things.

John

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PostPosted: Tue Jul 19, 2016 9:36 am 
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It's possible that there's a blockage in your pilot jet(s) - they're located under the small cover at the side of the carb facing the rear.

They have very fine jet holes - don't try and use anything solid like wire or a drill, you'll likely damage them.

Mine were prone to blocking causing an erratic idle and stuttering just off-idle; fitting a quality in-line fuel filter helped a lot.


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PostPosted: Tue Jul 19, 2016 10:38 am 
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Sounds like I need to take it off. What's the trick to getting at the bolt on the back? I can use a 1/2" crows foot for the front, not so easy to access the rear bolt.


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PostPosted: Tue Jul 19, 2016 10:43 am 
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Guys, double checking because it sounds like youre referencing the zenith carb, not the Weber. I did not see idle mixture adjustment at the base, and the cover that popped off the side contained a pivot point for the accelerator pump, not the Jets. Best I can tell, jets are internally accessible on the Weber carb


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PostPosted: Tue Jul 19, 2016 12:47 pm 
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Whoops! Yes - apologies I was talking about the Zenith carb - can't help with the Weber I'm afraid.


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PostPosted: Tue Jul 19, 2016 5:15 pm 
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Location: Gilbert,AZ
The back bolt for the Weber is a bit oa PITA, I use a cut down wrench for that teeney bit of a turn at a time. Both of my Weber trucks tend to be a bit cold blooded until fill warm-up. FYI.
Mark

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PostPosted: Tue Jul 19, 2016 6:14 pm 
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Location: Lewes, East Sussex - UK
Apologises from me as well - some how read the post to be talking about the Zenith - The Weber is different.

As far as it goes, all Carbs suffer from "sh*t" in the jets at some point during their operation. Boils down to have good fuel filters inline, and when you get a blockage, taking things apart and "blowing" clean the jets - main and idle if you can. Some carbs have the Idle jets built in to the Carb body so no way to remove and clean other than use compressed air with a suitable nozzle to direct the air down the correct hole(s).

Does you manifold have a PRE-heat pipe to warm the Carb? In other words is there a spur from the left hand exhaust pipe running under the Carb and then on to the silencer? If it does, maybe it is blocked? Some have a blanking plate instead of a gasket on the left hand side joint.

Sorry only general trouble shooting options as I don't know the Weber Carb specifically.

John

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PostPosted: Tue Jul 26, 2016 6:14 pm 
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Im curious... What is the exposed jet on the top of the carb? The one that points straight up through the center? Why is it exposed? It doesnt seem adjustable


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PostPosted: Wed Jul 27, 2016 7:05 am 
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I've cleaned both carbs on my 1bbl carb trucks,but it's been a while.But I think it's the main jet,to be changed w/cliamate and or altitude.
Simple carbs, the float issues seem to be the biggest headache (per Jim L. the U.S. Guru of Haffys)! 8-)
Mark

_________________
62 haffy
68 haffy
TGB 1317 Volvo
Dnepr M/C
FG140 Fuso
3 other boring cars!
and 2 more motorcycles
Oh yea! my John Deer lawnmower
leaf blower and a Weed Wacker!
Just poking fun at sigs! ( ) smiley face goes between the brackets....


Top
 Profile  
 
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