Hey guys, what's up? I just got my 84 GS w/ 49,260 miles home yesterday and am trying to get this cherry running.

Now, I shouldn't say she's not running, she is starting and making smoke and all that good business, but never for very long. After I finally got it to run at all, after it hadn't run since Octoberish, it's not holding an idle.

I have to have the choke pulled out and really give it gas for it to do anything but die. When it first started and the choke was doing its own thing, it was actually running, as soon as the choke closed, the engine died.

I know nothing about carburetors, and next to nothing about the first gen engine bay. I already have a 87 FC with about 200,000 really rough miles, and this little cherry of mine is going to be a blast, once it idles!!

I also checked the spark plugs, they weren't horrible. I guess I could clean them up, but if it is actually running, just not for long, I don't think they would be the source.

 

I'm right there with you!

I have the exact same problem, and I'm pretty sure it's a gummed up carb. If you can get someone to help you start it, look down in the barrels and seeif the smaller two are getting fuel from the jets.

One of those don't spray and the car won't idle, but the big jets will be enought to make it run while you give it gas.

Anyone feel free to correct me if I'm wrong.

 

That is what I was thinking, but I'd rather not get all gung ho with carb cleaner and blow **** up.

50,000 miles isn't enough for a carb teardown, but 23 years sure is.

 

With that few of miles on the engine, a varnished up carb is a strong possibility. In my sig line is a link to the online FSMs, carb manual, etc.. Download what you need and take a serious look at rebuilding the carb.
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I got a Hayne's manual with the purchase, but it's good to know a FB FSM.

 

The factory carrb manual is even better. I covers all the differences between the 1st gen carbs and also goes into some theory on how the Mazda carbs work/

 

Change your fuel filter for starters if you haven't already....

 

Once you get her running, you'll have to come over on the Ferry for a meet or an autocross.

If this was my car, this is what I would do at this point:

1. Basic tune up items. Cap/rotor/plugs/FUEL FILTER/oil change. Also, depending on their condition, maybe some new plug wires.
2. One can of Seafoam through the gas tank (if you can get it running). Otherwise, just dump an ounce or two down the carb and crank her over. Seafoam is great for cleaning out any buildup inside the motor, and the varnish inside the carb probably doesn't like it very much either. The stuff works great!
3. If none of this solves the issues, I would either find another running carb to try out or rebuild the one you've got.

Good luck with it man. I've got an '85 GS w/211,000 miles on it that I race all the time. Take good care of her, and excercise her daily, and she'll take good care of you in return.

 

New filter and pump as of last fall.

 

Our fuel filters don't typically last long because of the rusty old tanks on these cars. If I were you I'd go ahead and change it. It's worth the $3 just to rule it out.

 

Fuel is good going in. We think the floats might be stuck.

Guess it's rebuild time. Yay. I can't wait.

 

All the other advise is great for your problem. In fact I've just finished a complete fuel system rebuild. I've never heard of the floats sticking closed. Mine stuck open and literally flooded the carb. That is to say it ran over with gas.

Your problem may be much simpler. The First Generations have a little bimetal flap called a temperature compensator and when they go, your car will not idle especially in cooler wheather. It's inside the air filter. Before you go tearing it apart, have someone work the choke/throttle while you press down on it with your thumb. If it idles, its your problem. You can do what I did and take it apart and bend it closed, or just plug the vacuum line connected to it. Its purpose in life is to step your idle down under extremely hot running conditions. Otherwise your car will idle at about 1000 rpm. Personally, I can live with that. Mazdatrix just wanted too, much for what this thing is.

Also, as I mentioned, I rebuilt my carburator for the second time in 12 years worth of ownership of this 1985 GSL, and this time for some reason the choke doesn't raise my idle. I'm really hoping this isn't an internal vacuum leak. Does anyone have a clue?

 

As it turns out, there was a problem that I had noticed, but thought is was part of the design during my previous rebuild. On the end of the main throttle shaft toward the rear of the carb, there is a metal bracket that runs back down the length of the shaft toward the horn assembly. Everything, and I mean everything intersects with this metal piece. The throttle pulley is the first, followed by the cruise control pully, the hot start assist pully, next to last in line in front of the secondary throttle linkage to the other two barrels and at the point of greatest deviation was the choke linkage arm. As it turns out the tongue was bent at a downward angle apparently from normal use. Bending it back to run straight along the throttle shaft fixed all of my problems, to include low power at high RPMs associated with not all barrels fully opening. I'll eventually have to somehow find a new piece because of metal fatigue but for now, it just purrs.

 

Great news man, and thanks for updating us...