Beaver Posted October 7, 2012 Share Posted October 7, 2012 cartbed a12, just rekitted carb over the weekend (in retro spec I shouldnt have, its caused more problems that it was worth, should have just replaced the seal/gasket that was buggered.....but anyway) now it will surge/stumble at idle (its fine when dirving, smooth as kks mum nether reigons). not all the time, but probably over 50% of the time. It is alot rougher then beofre I pulled the carb apart so short of pulling it apart again is there anythign else it might be? I have the mixture screw set at two turns out (as per manual) so should I have a little play with this to see if it tightens up the idle? Would a vacum leak cause it? and is it worth looking at the ignitions side of things as well? Cheers Quote Link to comment Share on other sites More sharing options...
Steelies Posted October 7, 2012 Share Posted October 7, 2012 check for vac leaks and give the screws another once over, hopefully without stripping them where was the mixture screw set pre rebuild? Quote Link to comment Share on other sites More sharing options...
Beaver Posted October 7, 2012 Author Share Posted October 7, 2012 where was the mixture screw set pre rebuild? good question..... Hopfully its a vacum leak, the pipe for the PCV/PVC valve or whetever is just below the carb and is very shitty looking so fill replace that to start. Quote Link to comment Share on other sites More sharing options...
Beaver Posted October 8, 2012 Author Share Posted October 8, 2012 checked dwell and timing, dwell was way to high, dropped it to withi spec, reset timing to ~7 degrees at idle (hmm just remembered I didnt take of the dizzy vacum advance, shouldnt do uch at idle anyway). did fuel pump (the one in the carb), cleaned out pcv valve (when I blow into it now it actually seals) and found a crack in the hose from the valve to the block, right where it connects to the valve. didnt have any hose the right size so tape and a better hose clamp will do the trick for now. also the nuts holding the carb down wherent very tight.....wooops. reset the mixture as well. I think Ive got it pretty good as before the car would die if you gave it any choke (which means it is too rich as the choke makes it richer), and now it increases the reves if you put a bit of choke, but fll choke makes it run like shit/die. all this seemed to has helped more, definitly idles smoother. havnt driven it but it 'seems'; a bit more peepy from idle when revving Quote Link to comment Share on other sites More sharing options...
Rookie Posted October 8, 2012 Share Posted October 8, 2012 The vacuum advance does make a difference at idle Beave. Quote Link to comment Share on other sites More sharing options...
Beaver Posted October 8, 2012 Author Share Posted October 8, 2012 god damit, will redo tonight lol Quote Link to comment Share on other sites More sharing options...
Llama Posted October 8, 2012 Share Posted October 8, 2012 Infact, at idle (and low throttle) it has the most effect. Progress is progress though Quote Link to comment Share on other sites More sharing options...
Beaver Posted October 11, 2012 Author Share Posted October 11, 2012 right, is running a lot smoother which is good. Im sure something still isnt quite right though and it is quite sluggish in low revs (till about 2000rpm) and then is fine. super smooth and no stumbling or missing or anything, just seems far too sluggish. can almost feel it open up a bit above 2000rpm. My drive way is inclined, relativly steep, but it only just crawls up it with foot flat on the floor. same when moving off from standstill, foot dead flat, not mch untill about 2000rpm then its fine. timing is 7-8 degree at idle (750rpm), dwell is 51ish (spec is 49-55). mixture screw is set basically in the middle of it running worse (too rich or too lean) which is about 1.5 turns out from all the way in (says 2 turns out is a good starting point). is there a better way to set the mixture? any thoughts? I thought of fuel filter but its fine once it has a few revs so decided that wouldnt be it. cheers Quote Link to comment Share on other sites More sharing options...
cletus Posted October 11, 2012 Share Posted October 11, 2012 did you set the timing with the vacuum disconnected? Quote Link to comment Share on other sites More sharing options...
Beaver Posted October 11, 2012 Author Share Posted October 11, 2012 i did (the second time haha). it didnt really make a difference though....I couldnt tell any difference lookin at the timing marks. sucked on the tube and it advanced to its working to some extent Quote Link to comment Share on other sites More sharing options...
Llama Posted October 11, 2012 Share Posted October 11, 2012 I've always set the mixture by lifting the throttle plate slightly and seeing if the rpm rises or falls. That might just be for SUs though... What temperature is it at when it struggles with low revs? Quote Link to comment Share on other sites More sharing options...
Beaver Posted October 11, 2012 Author Share Posted October 11, 2012 yeh im pretty well schooled with SUs, this is a downdraft carb however so not sure if there is a similar trick. cold and hot, doesnt really change. Quote Link to comment Share on other sites More sharing options...
Slacker_Sam. Posted October 11, 2012 Share Posted October 11, 2012 I had a auto 120Y Sedan back in the day.... from what I recall it was unbelievably sluggish at low rpm. It struggled to get off the rolling road at the wof place. And steep-ish hills were always foot flat in "L" A manual conversion soon fixed that problem. Quote Link to comment Share on other sites More sharing options...
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