fshnidiot Posted August 11, 2008 Share Posted August 11, 2008 :banghead: OK, I've spent the last week reading and trying everything as far as tuning this Weber and I've noticed that most of these threads about backfire problems either fade out (Yeti,Slideshow86,ect) or end in a Weber for sale add. Has anyone ever FOUND the problem and fixed it? I have an 82 Brat with a fresh resealed EA81. DG series 32/36 electric choke weber that came with the brat when I bought it from lepetitprince that was rebuilt/modded and jetted for Subaru application by Cameron (former board member from Australia) in 2004. I've set the timing according to GD's instruction. I've put my 50 cents in the ASV's and sealed them off. Compression test shows 165 to 175 on all cylinders. I have 1 vacuum hose from the carb to the dist, 1 going to the cab for the heater controls, and my brake booster hooked up, all other vacuum ports are capped off except for the vacuum port on the back of the intake manifold under the carb where I have the vacuum guage attached. I presently have 19lbs of manifold vacuum at rough idle with no leaks I can find. I've followed all the tips on setting and adjusting the idle/mixture screws. I've tried 3 different coils and 3 different distributors in various combinations. New cap,rotor, plugs,wires ect. Fresh gas. I can get it to idle at 1100 rpm but it pops and backfires when under acceleration in neutral and it's even worse when under load. I have pulled my dist. and tried chasing my timing around and that hasn't helped either. It seems to run best at the farthest end of the adjustment range on the dist like I'm off 1 tooth but when I move it 1 tooth it moves all the way to the other end of the dist adjustments like it should be back 1 tooth if that makes any sense. I have the carter/weber 1bbl it came with, and a hitachi 2bbl on manifolds I could go back to but I HATE and don't want to replace all that vacuum hose mess 'cause I know I'll never get that back in there right. Sorry about being long winded!!! Any thoughts or ideas would be greatly appreciated!!! :banghead: Frank Link to comment Share on other sites More sharing options...
Yo'J Posted August 12, 2008 Share Posted August 12, 2008 I had to use a timing light after I replaced the manifold bolts and gaskets causing my manifold leak to get mine to work right. I chased issue after issue and now I get o.k. mileage but my motor has 220k and doesn't rev so fast. Everything was worn on mine, the distributor rattled like a pebble in a tin can till replaced. I don't believe it ran at all. I've stripped almost everything else off but the asv and the heater controls. I'm about to open the catalytic converter as well. She is now almost perfectly tunable, easily, and works as my daily driver. I can bury the needle and idles fine, finally. Some of the hose placements I still find confusing but they havent caused a problem yet. So much info and variabilities on the internet I wish I had someone to double check mine. Not being a trained mechanic doesn't help in my case. You sound so close! Do you have a fuel pressure regulator? Webers can't take more than 3.5 lbs. before they just overflow and I find the floats are tricky. I run at 2.5 to 2.75lbs fine. I don't know anything about the possibilities of the ecu in relation year or type of the distributor causing your problem though. I've noticed 82 is a weird year. Link to comment Share on other sites More sharing options...
mcbrat Posted August 12, 2008 Share Posted August 12, 2008 how many turns out is your idle mixture screw? (mine have never been in the "normal" range of turns.) how many turns on your idle speed screw after it contacts the throttle lever? Link to comment Share on other sites More sharing options...
fshnidiot Posted August 12, 2008 Author Share Posted August 12, 2008 I'm at approximately 2 turns out. Anything below 1000rpms and it tries to sputter and die after it's warmed up to normal operating temp. Mixture screw on the primaries runs smoothest right at 2 turns out so I'm sure it's jetted right. Secondaries are at 1 1/2 turns. I believe edrach has a few of Cameron's Webers on his Brats and has had no problems and all I've read here says he (Cameron) knew what he was doing in rebuilding these carbs. I don't have a fuel pressure regulator in there but my fuel pressure is between 2 1/2 and 3 lbs. right where it should be. I'm tempted to try switching it over to my good running 81 and see if the problem is the Brat instead of the carb but I'd have to dig into all that vacuum mess and I don't want 2 Brats sitting in my yard not running. I am vacuum hose illiterate when it comes to these subies. Thanks for answering, any other ideas welcome please. Frank Link to comment Share on other sites More sharing options...
bigjim5551212 Posted August 12, 2008 Share Posted August 12, 2008 I think you have a vacuum leak still. Get a can of WD40 and spray it around all the gasket areas. Check as well, your power brakes. The diaphragm could be leaking. Check as well, the throttle shaft of the Weber. They do wear. We have a throttle shaft bearing kit that takes care of those issues. The secondary should not be adjusted. The secondary throttle plate should be closed and the screw should be peined. Link to comment Share on other sites More sharing options...
bigjim5551212 Posted August 12, 2008 Share Posted August 12, 2008 The idle speed should be smooth and not hunting. The idle speed screw should be able to be turned out to reduce the engine speed, all the way to stalling. The same with the idle mixture screw, it should be able to be turned all the way in to stall the motor. If the idle speed screw gets turned all the way out and the engine still runs, then there is a problem with the cable maybe. Something is not letting the throttle plate close all the way. Link to comment Share on other sites More sharing options...
Recommended Posts
Please sign in to comment
You will be able to leave a comment after signing in
Sign In Now