Backfiring |
|
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG.
This site is not affiliated with Porsche in any way. Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners. |
|
Backfiring |
BfloRandy |
Apr 10 2017, 06:02 PM
Post
#1
|
Dimwit Extraordinaire Group: Members Posts: 66 Joined: 20-September 14 From: Buffalo, NY Member No.: 17,927 Region Association: North East States |
Happy Spring, aka fix your car so you can drive it all summer!
Having an issue tuning my Weber 40's. The car does run, and idles quite well, sounds smooth and even. If I rev beyond 3k, I get backfires. Starts fine too. Ordinarily I would assume it's a simple matter of resetting and resyncing. Passenger side carb is as it always has been, fine. Mix adjustment screws work normally, idle adjustment also. I see the squirt from the accelerator jets. Driver side, not so much. It's getting gas. For some reason, the mix screws have little to no effect. This is on BOTH cylinders. The only time I notice any change in the engine's sound is if I back them way way out, then I get backfiring and carb throat sneezing. Otherwise, I can have them set just about anywhere, including fully seated, and there is no difference. I've pulled the carb off, (three times now) torn it down and blown everything out a couple of times already. I did see some blockage in the idle jets and mains before I blew them out. I also noticed that I didn't see any squirt from the accelerator jets. I tore it down again, and fiddled with the pump (new last spring) and reassembled it. Accel jets now appear to work normally. It doesn't at all help that my kids decided to reorganize a ton of things, and I now can't find my Weber manual. (IMG:style_emoticons/default/chair.gif) Can anyone help? Thanks! |
BfloRandy |
Apr 24 2017, 03:13 PM
Post
#2
|
Dimwit Extraordinaire Group: Members Posts: 66 Joined: 20-September 14 From: Buffalo, NY Member No.: 17,927 Region Association: North East States |
Most recent update:
Just replaced points, rotor and condenser. Dwell at 45 degrees, timing set at 27 BTDC at 3200 rpm. Idling at 1400. Idle adjust screws are backed off of the stops. Only way I can get it lower is to manually pull up on the droplink (hard) on driver's side carb. This gets it down to 11-1200. Still getting popping (not full blown backfiring!) when revving, so that is an improvement. I suspect that I need to dismantle the one carb and find out why it isn't closing up completely at idle... Could this also be the cause of the backfires? |
Lo-Fi Version | Time is now: 10th June 2024 - 07:28 AM |
All rights reserved 914World.com © since 2002 |
914World.com is the fastest growing online 914 community! We have it all, classifieds, events, forums, vendors, parts, autocross, racing, technical articles, events calendar, newsletter, restoration, gallery, archives, history and more for your Porsche 914 ... |