Hey guys. Little carb problem. After searching the relms of google and the almighty forum search bar, i have tried to diagnose why my '84 340 GL is rubber banding slightly. They're not massive surges, but noticeable kangaroo lurches. The first chamber, when i hit the throttle, has the small jet a fuel going into it, the second does not which as far as i can tell is good. however, the second chamber butterfly does'nt open when i push the throttle. Stupid, but does this open only when its running, or when at full throttle, or should it open at the same time as the 1st chamber? also, im missing a choke plate from the second chamber. Im not too familiar with carbs, so i may just be being silly.

1st chamber on the right, second on left.

http://farm5.static.flickr.com/4074/485 ... 110e_b.jpg

missing chole plate, second chamber.

http://farm5.static.flickr.com/4137/485 ... a5fb72.jpg

Otherwise, i have just replaced the HT leads and spark plugs, and the engine definatly runs smoother. i'm yet to test it driving to see if its done anything with regards to the kangarooing. Either way, if any of you have any ideas as to why the lurches could be happening would be greatly appreciated.

Cheers in advance

Jon

To answer your second question, no, there should only be one choke valve, even when it looks like one is missing.

except for the carbs on a B14.0, B14.1 and B14.2 engine's; those do have 2 valves, wich is stupid really.

it's normal about the 2nd butterfly; this carb is designed to be economic or give performance when the driver wants to.

if you drive calm, and don't go further than 2/3 of the throttle, you only use the 1st barrel (hence only 1 choke valve; what idiot would floor it on a cold engine....) and with this you're economic.
but if you want some speed and go further than 2/3 of the throttle, the 2nd barrel gets into action and allows more mixture in the combustion chamber = more power, 8 horses to be exact

about the kangarooing; if you could read dutch i could type a whole book for you with things to check. but as i'm a bit lazy today, here's a start: http://www.volvo300mania.com/forum-uk/v ... ?f=6&t=571

to me i guess the 5 bolts on the floaterchambercover are loose or you have a vacuumleak from one of the hoses near carb base/ intake manifold

good luck

so i was just being silly. I thought that might be the case for the second butterfly. Ive seen that thread before, now i know what exactly im looking for, i will do that. cheers for the help guys.