croak Posted June 28, 2019 Share Posted June 28, 2019 Running an 80 brat with weber. I’m getting horrible gas mileage(mid teens). Seems to run good, carb is adjusted and falls with in specs(idle and mixture). Cap and rotor don’t look bad, Im running a junk yard coil, and rebuilt 83+ disto. All smog equipment is bypassed, disto is only vac line used. I smell gas on hot days, how much could I be loosing to evaporation. Should I reconnect the charcoal canister system? Could low fuel pressure cause bad mileage? Plugs look good. coil? Plug wires? I have checked for vacume leaks, i think I'm good. I am not expecting anything great, i seldom hit the freeway, and my average drive is <2 miles. Any suggestions would be greatly appreciated. Thanks in advance IC Link to comment Share on other sites More sharing options...
carfreak85 Posted July 1, 2019 Share Posted July 1, 2019 Does your Weber have a return line to the fuel tank? Link to comment Share on other sites More sharing options...
croak Posted July 1, 2019 Author Share Posted July 1, 2019 No, just direct connection from fuel pump. Link to comment Share on other sites More sharing options...
carfreak85 Posted July 1, 2019 Share Posted July 1, 2019 There's your issue. First off, your fuel pump is probably overfilling the carb, IIRC Webers want only a few psi of fuel pressure and the stock pump pushes a few psi MORE than the Weber likes. You may need a pressure regulator. Also, your fuel tank wants to be vented, so make sure that you haven't capped off the return/vent lines, or on hot days you'll have a pressurized fuel tank pushing even MORE fuel into your over-fueled carb. Link to comment Share on other sites More sharing options...
croak Posted July 1, 2019 Author Share Posted July 1, 2019 How is the return line routed from the weber, i haven’t seen this before. The vent still leads to the charcoal canister. I was under the impression that the weber wanted the same fuel pressure that the stock pump puts out. Link to comment Share on other sites More sharing options...
carfreak85 Posted July 1, 2019 Share Posted July 1, 2019 I'm no Weber x Subaru expert, I play more with the fuel injected/forced induction Subarus, new and old. Link to comment Share on other sites More sharing options...
naru2 Posted July 1, 2019 Share Posted July 1, 2019 (edited) The stock pump is 1.35-2.06 psi.Certainly not more than the Weber likes. You will be hard pressed to get higher mileage w/an average drive <2 miles. New cap and rotor is almost always good for at least a slight improvement. If it does not stall,overfilling is quite unlikely.You can add a fuel return by swapping the Y fitting from the inlet of the old carb. Edited July 1, 2019 by naru2 Link to comment Share on other sites More sharing options...
carfreak85 Posted July 1, 2019 Share Posted July 1, 2019 Guess I must either be thinking of EA81+, or Toyota 3A Weber conversions... Link to comment Share on other sites More sharing options...
croak Posted July 3, 2019 Author Share Posted July 3, 2019 Thanks guys, i swapped plugs and wires, cap and rotor look good, they are pretty new. Checked timing, and it is sitting at 14*. I am out of room on adjustment. Running 83+ distributor and diy bracket, im going to try getting a bracket from pick and pull, see if that helps. 1 notch on disto was to far. Will update if it helps. Link to comment Share on other sites More sharing options...
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