high winder Posted September 28, 2015 Report Share Posted September 28, 2015 okay so I had some troubles here awhile back with the dizzy somehow coming loose. got all that fixed and things were running fine. then on Thursday I go to start it and noticed it drug when I started it like the timing slipped. anywho I drive home and all is well until the following day. starts dying as soon as I let off the gas, runs rough etc. I check timing i'm right at 5 BTDC, when I hand throttle it, it advances on up to 20 like it should I think, I looked for vacuum leaks and didn't find any, it idles like a champ, it revs perfect when I throttle it with my hand off the carb but when I try and drive it the car falls on its face, doesn't want to rev, runs like chit. not sure if its timing, a bad vacuum advance or something else. elec ign. and its a 5 spd any advice would be greatly appreciated Quote Link to comment
tr8er Posted September 29, 2015 Report Share Posted September 29, 2015 So it runs great until the clutch is engaged? Quote Link to comment
datzenmike Posted September 29, 2015 Report Share Posted September 29, 2015 When driving, your foot goes to the floor and power drops off and you have to let up just to keep a steady speed? Car goes slower and slower up a hill? Will go faster down a hill but on the level, drops back to the same speed as before. It revs up ok in neutral because it doesn't take much gas to spin 50 pounds of crank and pistons. But pull 2,000 pounds of car along? forget it. If you can drive it as much as you can under load, say 10 min. Pull a plug. If the porcelain tip is bright white you are running over lean. Primary jet is likely part clogged. Lean running overheats the plugs and burn all the deposits off. White porcelain ... lean. 1 Quote Link to comment
high winder Posted September 29, 2015 Author Report Share Posted September 29, 2015 yep you got it, idles revs great until under load then it falls flat goes slower and slower up hill, wants to back fire sometimes... so I pulled the plugs and they are all just very light tan color, no wetness, oil residue nothing. okay so on the weber 32/36 do I just look into it and unscrew the jets or are they on the side somewhere?? you guys rock Quote Link to comment
tr8er Posted September 29, 2015 Report Share Posted September 29, 2015 yep you got it, idles revs great until under load then it falls flat goes slower and slower up hill, wants to back fire sometimes... so I pulled the plugs and they are all just very light tan color, no wetness, oil residue nothing. okay so on the weber 32/36 do I just look into it and unscrew the jets or are they on the side somewhere?? you guys rock Your turn. Go look up a jet replacement how to on Google. Then clear the clog. It's easy, Quote Link to comment
tr8er Posted September 29, 2015 Report Share Posted September 29, 2015 Fuck it http://www.mk3supra.org/topic/561-guide-rebuilding-a-weber-3236-dgav-carb/ Quote Link to comment
high winder Posted September 29, 2015 Author Report Share Posted September 29, 2015 Now that's a SBS... My hat is off to you good sir. Quote Link to comment
ericsb210 Posted September 29, 2015 Report Share Posted September 29, 2015 Check your fuel line for blockage....better yet just blow it out, replace the filter and give it a go. Quote Link to comment
datzenmike Posted September 29, 2015 Report Share Posted September 29, 2015 Possibly that, but I've had this on a B-210 and the engine sputters and jumps on and off like running out of gas. The plugged jet seems like power just drops off as you push the throttle down. Carb makes a louder groan as more air is added until the mixture is so weak it will sometimes backfire. Plugs were whiter than new Try it, it's only $4 or $5 for a filter and no harm trying.. Quote Link to comment
high winder Posted October 5, 2015 Author Report Share Posted October 5, 2015 Okay..Got it all tore down and installed back on the car. Runs like a champ with way more power but.... It idles really high and I'm adjusted all the way out. Timing is good so my question is what could cause it. The primary and secondary jets looked like the same size so I didn't pay attention which one went where. When I pulled the imultuon tubes the primary was a real PITA , when I got it out I noticed a small crack by one of the holes, since I didn't have another I reinstalled it. Could this cause the high idle. Thanks for the SBS, gigantic help. Quote Link to comment
datzenmike Posted October 5, 2015 Report Share Posted October 5, 2015 Fast idle causes... Throttle cable too tight Choke on or not shutting all the way off causing fast idle cam to engage or fast idle cam stuck. Secondary throttle plate stuck part open or foreign object caught in it. Primary throttle shaft worn causing misalignment and sticking of throttle plate. BCDD set too sensitive and not releasing. Timing too advanced because idle too high upsetting vacuum and mechanical advance. Quote Link to comment
Doctor510 Posted October 5, 2015 Report Share Posted October 5, 2015 yep you got it, idles revs great until under load then it falls flat goes slower and slower up hill, wants to back fire sometimes... so I pulled the plugs and they are all just very light tan color, no wetness, oil residue nothing. okay so on the weber 32/36 do I just look into it and unscrew the jets or are they on the side somewhere?? you guys rock The Idle jets are on the sides, mains are at the bottom of the float bowl, Try clearing the Air Corrector jets with carb cleaner at a high idle through the top pf the carb, you can see them, w/o removing the top Quote Link to comment
high winder Posted October 5, 2015 Author Report Share Posted October 5, 2015 I'm gonna take a look at the secondary throttle plate, when I was putting it back together it just didn't quite Want to close when I ran the linkage, I noticed it had a tiny burr on the very edge of the barrel where the shaft comes out. I cleaned it up with 1000 grit emery cloth until it worked. I'll check bushings as well. Quote Link to comment
high winder Posted October 6, 2015 Author Report Share Posted October 6, 2015 Datzenmike what is BCDD an acronym for? Quote Link to comment
high winder Posted October 8, 2015 Author Report Share Posted October 8, 2015 got the fast idle taken care, had a gap in the secondary butterfly that left about a thumbnail gap. unscrewed it, flipped it around and wah! la! thanks for the help fellas Quote Link to comment
datzenmike Posted October 8, 2015 Report Share Posted October 8, 2015 Boost controlled deceleration device. On deceleration the carb is at idle but the intake vacuum is very high from the high RPMs.The mixture that enters the cylinder is very weak and does not burn well and lots of un-burnt hydrocarbons are dumped out the exhaust. When the intake vacuum rises above a pre set limit the BCDD opens a small passage and mixes a proper amount of gas and air and feeds it to the engine so it can assist in the complete combustion and lower the HC level. It's basically a very small carburetor within the carb. When the vacuum level drops the BCDD shuts off. It is possible for the BCDD to be set too sensitive and normal intake vacuum will hold it open and raise the idle speed. Quote Link to comment
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