I have a FB GSL with a 12A. The engine idles okay with the choke pulled out. But, after it warms up and the choke releases, it won't keep running during idle unless I keep the choke **** pulled out with a quarter lodged behind the ****. If I let the choke **** retract, it will only continue running if I keep my foot on the gas. The engine will even die on the highway if I take my foot off the gas.

The idle adjustment seems okay, and I've replaced the plugs and wires, air filter, and checked all of the vacuum hoses with no improvement. I don't think it's the shutter valve since I don't hear that characteristic honking noise that it makes when it goes bad.

It did this a few years ago, and I took it to a local import shop that fixed the problem. But, they are no longer in business and I don't know what they did to fix it. Any suggestions on how I might fix this problem myself?

 

you can tighten the throttle cable up to pull the throttle open just a hair

When you have the Choke pulled out it increases the throttle just a little and about 3/4 way out it turns the choke flap.

 

I had to goose the engine at stop lights. Everyone thought I wanted to drag...

 

My 83 GSL 12a had a layer of crap in the bottom of the float bowl when I bought it. After driving for a month it would die at idle (but it also lacked high end power). Cleaned it out and replaced the fuel filter, which was not even a filter anymore. Check your fuel filter, it may be plugged beyond funtionality like mine was, spewing sediment into the carb. Not a fun problem to deal with any way you cut it. Good luck!

 

Just an update: I did a vacuum leak test and noticed a slight increase in rpm when I sprayed starting fluid back around the firewall. I still could not isolate the leak, so I called Mazdatrix and one of the guys there (Mike?) told me it was the anti-afterburn hose. He said it gets a soft spot on it at the bottom of the hose near the exhaust. Sure enough, it was soft there and had a very small split in it. I fixed it with some high temp tape until the new one arrived and it now runs like a champ!