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weber sidedrafts


Guest Anonymous
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Guest Anonymous

i bought a 69 with weber sidedrafts last fall and finally get to tinker with it

it seems that only one carb - the rear one - is engaged in idling the engine - and the engine sounds as though it has dead miss at idle

however - when you accelerate - it scoots pretty good

i have taken apart the cold start system and it seems operable - both seats appear to operate - and i have taken the jets out and sprayed carb cleaner through them and the channels - none appear to be blocked

at high idle and though acceleration (in nuetral!) i can block the intakes on the front carb with little effect on the engine operation - leading me to believe that the front carb is problematic and that when the engine reaches higher rpm the front two cylinders are stealing fuel from rear carb through the intake

any comments?

thanks

bob

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Guest Anonymous

Hmmm...Did you check the fuel level in the front carb? First verify the is is getting fuel. There is no way for the front two cylinders to run off the rear carb, thay are not connected in any way. If the front is getting sufficient fuel, check for spark to the first two cylinders.

You mention that is seems to run at higher RPM fine, so I would also suspect the idle jets on the front carb as well.

I have a set on my bar at home if you need me to look at anything for you, let me know.

HTH

Neil

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Guest Anonymous

unless you have some kind of equalization tube you can

steal fuel from one carb to the other. If you say it runs good with the throttel open then It sounds like

you need to syncronize your carbs.

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Guest Anonymous

OK, first you MUST synchronize the carbs. Without perfectly sync'd carbs, your other tuning efforts will be an exercise in frustration. I don't know what sort of linkage you have, but make sure it is set up properly and evenly or you'll have further headaches.

Once you've done that, baseline the idle mixture screws to make sure they are even across all four. Set float levels carefully (even half a millimeter matters in Webers) and make sure the needle and seats are operating freely. Finally, check your fuel flow - again, I don't know how the lines are set up, but if they go from the pump to the rear carb and then on to the front (as they do on my car) you could theoretically have a supply problem to the forward carb (unlikely based on your description, but worth checking). Make sure the choke isn't leaking, stuck, or out of adjustment (open) on the rear carb. If none of this solves the problem, your butterflies may be out of alignment and you'll have to yank the carbs to correct that.

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