Hi!  I have had a frustrating year of working on my new old suby.  I bought it for $300 from a friend who is a terrible girl driver...typical. She tried to drive it like a race car...I had a new Weber carb put in it because it would not hold idle but runs amazing. After the new carb I took it to Moab and it started popping and ticking under hood or backfiring out of carb.  (I have had a mechanic look at exhaust manifold for leaks, nothing.) I also had them test fuel pump because I changed the filter in Moab and it workd 100% better for bout and hour.  There is also a gurgling noise coming from heater core, I am told this is a leak and air is getting into the system.  It runs great up to speed but doesnt have much power getting there and idle is all over the place. sometimes its great, sometimes it suks! If any one has any advise for me please let me know. I want this car to be more than a grocery getter. And I need to go climbing soon Thanks!

Gurgling in the dash is the heater core.  Probably a bit clogged but still flowing.  You may or may not have air in there......I'd say it's not related to your idle/running issues.

 

Running issues could be crap in the carb bowl pluggin the emulsion tubes.

 

Although poping and backfiring would indicate timing too far advanced.

Year? Have you changed the fuel filter(s)? Check all your vacuum lines and carb mounting, lack of power and erratic idle sounds like a vacuum issue. Gloyale is spot on about the gurgle. Timing for a Weber can be tricky. Keep bumping it around till you find your sweet spot. I've done the Weber swap on 2 EA81's and each was a bit different on the timing.

ea81s like a little less addvance about 8-10

1986... Thanks gonna check the timing. I thought it was a vaccum issue but have found nothing. Also changed fuel filter and checked pressure on pump.

first thing is to check your vacuum advance line and make sure its hooked to the proper port.  if you just swapped the carb its likely that you have it hooked to manifold vacuum which would give you 30-40 deg of initial timing depending on where the static is at.  that could be why you dont notice it once you get to speed since that is when the motor normally wants it to be that high.

 

you should also check your timing components.  check that the timing belts are tight and not able to flop around.  Pull the distributor cap and make sure the rotor is seated and in good shape, and that it is movable by hand and springs back into place.  also check your vacuum advance to make sure it will hold a vacuum (just suck on the tube and block it with your tongue, if it holds your good).  all those except maybe the belts are 1 min checks with just a screwdriver, and worth a look.  then of course put a timing light on it.