SupDoc Posted October 30, 2021 Report Share Posted October 30, 2021 I'm trying to tune the Weber 32/36 that is on my stock L16. When I back the idle screw all the way out, it idles in the 1300rpm range. I can get it to idle at 850-900rpm, if I turn down the mixture screw to only a half turn out. The car seems to drive okay at this setting, but the Weber instructions say the mixture screw should be around 2 turns out. So, I experimented with smaller idle jets, that didn't seem to make any difference. I went from a #60 all the way down to a #45. I even turned down the timing advance from 15 to 10 degrees, to lower the idle RPM. Does anybody have any other ideas that I could try to slow the idle, while keeping the idle and mixture screws set to Weber specifications? Quote Link to comment
d.p Posted October 31, 2021 Report Share Posted October 31, 2021 Is your throttle cable too tight? If it is thet could stop you from dropping g the idle lower. I think on my old l16 and Weber I could idle it down to where it would stall by tuning that screw all the way in. Quote Link to comment
SupDoc Posted October 31, 2021 Author Report Share Posted October 31, 2021 I disconnected the throttle cable to make sure, but that doesn't seem to be the problem. Quote Link to comment
fiveoneO Posted October 31, 2021 Report Share Posted October 31, 2021 Maybe there's a vacuum leak. Quote Link to comment
Stoffregen Motorsports Posted October 31, 2021 Report Share Posted October 31, 2021 Yeah, probably a vacuum leak, but could also be bound up linkage. Have you had the carb apart recently? Did it run fine before? If so, what happened? Quote Link to comment
SupDoc Posted November 7, 2021 Author Report Share Posted November 7, 2021 I just wanted to report back and thank you guys for the suggestions. It turns out that I did have a large vacuum leak around the EGR block off plate. I cleaned up the mating surfaces and resealed the plate. After eliminating the leak, I was able to get closer to the Weber specifications by replacing the #60/#50 idle jets with #55/#45. The mixture and idle screws still aren't in the proper range according to the operating manual, but I've decided not to worry about for now, since the car seems to be running fine. Quote Link to comment
datzenmike Posted November 7, 2021 Report Share Posted November 7, 2021 On 10/31/2021 at 9:08 AM, fiveoneO said: Maybe there's a vacuum leak. On 10/31/2021 at 9:55 AM, Stoffregen Motorsports said: Yeah, probably a vacuum leak, but could also be bound up linkage. Have you had the carb apart recently? Did it run fine before? If so, what happened? Ive never seen the idle go up when there is a vacuum leak. Why would it? If the idle mixture is set for best idle, allowing more air in would lean it out and drop the idle. The only way the idle could go up is if the mixture is already excessively rich or the choke is on. (same thing) 1 Quote Link to comment
Stoffregen Motorsports Posted November 7, 2021 Report Share Posted November 7, 2021 If you have a leak and start tweaking on the carb to get it to run, you probably just gave the engine more fuel. Add that fuel to the new source of air, and idle has just been bumped up. 15 hours ago, datzenmike said: Ive never seen the idle go up when there is a vacuum leak. Why would it? If the idle mixture is set for best idle, allowing more air in would lean it out and drop the idle. The only way the idle could go up is if the mixture is already excessively rich or the choke is on. (same thing) Quote Link to comment
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