Hi there, this is going to be a long winded question. So about 2 nights ago, I installed a Weber 32/36 on my '90 Mazda B2200. (2.2 Motor with the 5 speed.) I followed the instructions to a tee. I however did keep the EGR stuff for the time being. Every other wire got cut or removed, same with all the unnecessary hoses. Upon, the first fire up. It cranked for a good solid minute, then blew white smoke out of the air induction pipes, and thick white smoke out of the tail pipe as it ran.

I immediately shut the truck down, due to the thick cloud and the oil getting thrown out the air induction pipes. After that it started to pop, sort of like a backfire but like this pop pop pop, as I was cranking it. It first started to do this out of the air induction pipes. I promptly removed them and installed hydraulic dash 6 caps to the ports and made a block off plate. Same result, only now out of the tail pipe. The pcv valve, has been removed due to me breaking it, after trying to remove it to fix the oil leak out of the valve cover, and to paint said valve cover.

Has anyone else had this problem, if so know a fix to this. Could it also be a carburetor tuning issue?

 

First thing to do is to get a new PCV valve re-installed......it needs to be there. Also, the Weber will need to be adjusted......to find the "Best Lean Idle" as the installation instructions detail.

Once you have those done, let us know if it has cleared up the popping issue.

Also, sometimes the adapter plates will need to be "sanded or filed flat" to prevent a vacuum leak around or between them.......if you think yours is leaking, you can check them by spraying Brake or Carburetor Cleaner around the adapter plates while the engine is idling......if you do this and the idle speed changes, you probably have a vacuum leak there.

 

So I have not gotten to get the best lean idle mixture just yet. However, the popping issue just cleared up after changing the distributor cap, as the ignition coil terminal was quite corroded. Now there is a new issue, it wants to rev it's brains out. I believe the throttle is not returning on its own, as I drove back from the test drive and I barely had to touch the throttle as it kept accelerating on its own. (Note: Once in gear, it seemed to drop RPM'S, as one would suspect)

 

Make sure that you do not have the throttle cable tightened (adjusted too tight with the 12mm cable nuts) too much. With your choke in the wide opened position (engine OFF), and the tip of the Idle Adjustment Screw resting on the base circle of the throttle shaft "cam", you should have a 1/16" to 1/8" throttle cable "slack" in the cable itself........this way, the throttle return spring can "hold" the throttle closed at idle.

Also, make sure the throttle spring is not binding and has enough tension to pull the throttle closed at idle.

Not having the "Best Lean Idle" adjustment done yet, could also be contributing to your high idle situation.

Let us know what you find out, and good luck with it.

 

BTW.......the "popping" could have been that your corroded distributor cap terminal was not letting every cylinder receive a spark when it was required to receive it, and raw unburnt fuel was being pumped into the exhaust because of this, and then the fire from the next cylinder combustion that DID receive a spark, ignited the raw fuel in the exhaust to create the popping sound. This is what would happen to engines that had older "points type" distributors, when the points or the accompanying condenser, starting going bad! Wet, unburnt gas was getting lit in the exhaust pipe! And if the muffler started collecting gas in it, and then got lit off.......BOOM! It would split the muffler wide open!

 

Yeah, I had a '64 Dodge D500 with the points, never had the muffler blow up on me, but I do recall that happening every so often. I checked the cable, (the nuts are not tight as I had loosened them when I removed the original carburetor), the cable has just a slight amount of slack. I had noticed that the throttle spring had popped off, as well as the nut holding the cable plate onto the carb. (The nut its self seemed to have backed off on its own). However, once I am off work. I will attempt to get the best lean idle. As well as fix the carb studs, as they seem to come loose after tightening them done, and then tightening the nuts down. ( I assume that is the root of a vacuum leak, since Ive never heard this but the truck actually whistled like a busted tea kettle.)

 

Pretty much of a necessity with these Webers to have to use a stronger throttle return spring. I posted about this way back in 2005 when I did mine.

Buy a new throttle return spring at the hardware or parts store; the one supplied is weak. I use Ace Hardware spring #22 seems like a good fit (2” long, 3/8” coil) but most likely the part numbers have changed in those 17 years....I made my bracket too.

 

I have a bit weaker spring on mine, but it has never broken on me either.......I picked it up at Ace Hardware also, but don't know the part number.

 

Ahhh, I see ok. I think that may be my issue. Like an idiot, I forgot to install one properly. I'm pretty sure, I could rob one off my squarebody. Since my square has been sitting for a near decade. I'll post an update, once I get everything together, and ditch all the emissions crap. Thanks for the advice though, hopefully I can drive my dawg again out of my shop soon enough.

 

Note that Axel has a spacer under his Weber carburetor, I don't use one. He's in Florida, I'm in Arizona.

I also see in Axel's photo that his genuine Weber also has a black choke heater like mine does. A genuine Weber will have "Weber" stamped/cast into the carb body in at least 2 places (you can see one in both his and my pictures) ; some think that choke color (white v. black) is a way to differentiate genuine from a clone, but that's not true.