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<x-charset iso-8859-1>I had both of my throttle shaft bushings replaced at RIMCO in California for $30 each plus shipping. Jason 68 Notch (Nadine) I proudly buy my aircooled parts and service from... The Bug Stop www.texasbugstop.com ----- Original Message ----- From: "Mark Seaton" <mark.seaton2@ntlworld.com> To: "Type 3 Mailing List" <type3@vwtype3.org> Sent: Wednesday, January 23, 2002 7:08 PM Subject: Re: [T3] Idle mixture adjustment > Jason wrote: > >Your problem is likely a vacuum leak. When you rebuilt the carbs, did you > >lightly plane the top and bottom halves on a flat surface with 220 or 400 > >grit wet/dry sandpaper? This will let you know if you have any "high" or > >"low" spots, which indicates that your carbs may be warped from engine > heat. > > >Yes, you might also look for slack in the throttle shaft bushings. ANY > >slack is too much. > > I sanded down the bottom of the main carb body where it joins the throttle > plate- it was very bowed but I think from overtightening of the mounting > nuts rather than heat. The Throttle bodies themselves looked fine. I did > notice a fair amount of slack in the throttle shafts which was worrying. I > reckon that this is the most likely source of an air leak but I've found a > great company here in UK who will rebush the throttle shaft with PTFE lined > bushes, line reamed to fit the shaft snuggly for just 15GBP per carb. This > sounds very reasonable to me and would probably last a lot longer than the > original steel on alloy bearing. They charge 159GBP for a complete refurb of > both carbs, way more than I want to pay, and anyway the rest of the carbs > looked fine. They specialise in restoring vintage carbs to concourse cond. > and had listed T3 PDSITs NOS for 50GBP each- they don't have any left ;-( > I have to check if they can supply me some new idle mixture screws- I read > someone say that these should come to a sharp point- mine don't. The RHS one > is more truncated than the LHS, but I checked the tip under a microscope and > it didn't look broken. It came to a turned looking flat end about .5mm dia. > which appeared to be plated the same as the rest of the screw. How sharp a > point did these really come to? > > Dave Hall wrote: > > >Can you check the CO level? > > I find about 3% CO works OK on my Twin Carb. Could be yours is fine and > > there's air getting in - at tick-over speed there is quite a big suction > in > > the manifold to screw up the mixture. > > 20 mp(imp)g seems a bit low, > > but maybe not far off for slow cold short journeys. > > Timing and valves are also important - are these OK on yours, Mark? > > I've checked and re-checked the valves and timing- they seem fine. The weird > thing is that when I first got the car, the valves had next to zero > clearance and the ignition was way too advanced-like 30 deg at idle! Yet I'm > pretty sure that it ran at least as well as it doesn't now! If I increase > the advance it does seem to pick up. I'm contemplating removing the pulley > wheel to check that has its woodruff key- maybe I'm really retarded after > all 8--o > I haven't had the CO level checked yet- when I'm happy that everything in my > control is as it should be, I guess I should- I'm sure it would tell me a > lot. I am still getting misfiring for a while at start up but that lessened > when I enriched the mixture 1/4 turn and changed one of the leads for a fat > silicon one. I think I need new HT leads and am in the process of (trying) > to get some really nice Beru leads and connectors. With that sorted, rebuilt > throttle bodies, and Jim's uni-syn to get the balance right, I'm really > hopeful that things will tune up nicely. > > So what do others get with "healthy" stock (carbed or FI) engines in town > driving- would be interesting to get an average. > > SIR.LANCE wrote: > > >that or they dont have the idle set proporly and are useing the mixture > >screws as idle? > >so to get a good running motor u run more fuel than air? kinda like a > cholk? > >rather than letting more air in via the butterfly valves? > > I don't think this would work as if you keep riching it up, the engine idle > slows and runs uneven again- it needs air as well, Its not running THAT bad- > your engine doesn't run as well cold with choke as it does when its warmed > up- it just shouldn't stall all the time. > > Thanks all for all the input- Bryan if I discover the secret I'll let you > know > > Mark Seaton > Orange '73 1600TA London > > > ------------------------------------------------------------------- > Search old messages on the Web! Visit http://www.vwtype3.org/list/ > > </x-charset>