Hi all,

I haven't driven my RX-7 in awhile, and I'm trying to get it up and running again. Right now, I'm having an issue getting the car to idle.

About a year ago, I messed with the idle mixture adjustment (I don't remember what I did) in order to get the car to pass emissions. The car passed emissions, and I didn't really drive it much after that point. About a month ago, I started the car and found that, while the car will start just fine, it will not idle. What happens is that the car will start immediately, the idle will hunt around and idle at around 2k RPM with the choke all the way out until it warms up. Once the car warms up, the idle will start to jump and it will die. Giving the throttle some gas just prolongs the dying, but it won't idle on its own. In general it feels like it doesn't want to rev freely, and it struggles to get to about 4k RPM.

I've changed the spark plugs and replaced the fuel filter to no effect. I've tried messing around with the idle mixture, but I don't know how to get it to a starting point, since it won't idle anyways. The car is an 83' RX-7 (California emissions). I'm guessing I might have to take the carburetor apart, but I'm trying to avoid doing unnecessary work, as I don't have that much time to work on the car anymore.

I appreciate any insights that anyone can offer.

 

do you have a copy of the FSM? if not, you can get one from: Foxed.ca

find the procedure for setting the idle mixture from scratch.

i would not recommend pulling the carburetor apart just yet. you should try to exhaust all other possibilities first. start simple.
maybe try cleaning it first.
check your plugs.
try changing your fuel filter.
confirm adequate fuel flow.
see where the fuel is in the float bowls. that sort of thing.

 

Yes, I have a copy of the factory service manual.

I'm not sure how I can follow the procedure for setting the idle mixture, because I had assumed the car has to be idle-able in order to do that. I have changed the spark plugs and the fuel filter, and no luck. I tried starting it again today, just to see, and it starts just fine (especially considering I haven't started it in awhile), but it will just not idle and seems very sluggish.

 

Nope, this is not true. If this was the case, you'd never be able to correct a bad running car that idled bad.

Just follow the process in the manual. If you have problems, then only make small changes (1/4 turn) and write down what you do in case you need to revert back to the previous setting. Only adjust one screw at a time and monitor results. You want to ensure the car is warm and the t-stat open before making any adjustments.

 

I looked in the manual and tried the setup for a rebuilt carburetor, I assume that’s what you’re referring to. No luck though. As before the car starts and will sort of idle until it gets hot and then dies again.

 

Maybe you have a bad ignitor. Sometimes when they start to go bad, they will be OK until they get hot. Try swapping the ignitors and use thermal paste.

 

Oh I forgot to say, I cleaned off the filthy fuel window on the carburetor, and I couldn’t see any fuel in there while running. It’s hard to get a good look due to the angle, but I couldn’t see anything. I don’t know if that could be the issue as well. I replaced the fuel filter when I started working on this issue.

 

If you don't see fuel halfway on the sight glass, that is the issue. There are two sight glasses. One forward and one aft. You'll need a mirror to see the back one. You'll need to hunt down the cause. Bad needle, seat, float, low flow, etc.

 

Do see if you can get a good look in both windows. As Kansas says, there is one at the front and one at the rear. The rear is a bugger to get a look at… defn requires a mirror on a stick and a flashlight. You should see the fuel half way up both windows, and you can check it after you shut off the motor as easier on the ears and hands. You may also need to rock the car to get the fuel in the bowls moving to make seeing the top of the fuel easier.

If you can’t see fuel in the windows, repost and let us know. I went through fuel bowl level hell for several weeks and learned a lot fixing it.

 

I decided to take the carburetor off, since it didn’t look too difficult. I’ve got everything off, but it seems like it’s stuck. It’s just the four bolts with the groove cut in the top, correct?

 

four 12 mm nuts hold the carburetor itself to the manifold. 3 of them are fairly easy to see, but one them is kind of hidden if you still have a stock engine bay. if you are removing bolts, then you're probably fooling with some other parts of the carbie.

the MOP rod needs to be removed, as do the MOP lines, fuel lines, a few vacuum lines and the throttle and choke cables.

 

Can you post a pic of where the four bolts are located?

 

Here are the 4 blolts locations holding the carb on.

 

Thank you.
After driving in 87+ degree weather, it wiil stall after the idle speed jumps around. If I keep the RPM above 1200 when stopped I can keep going.

 

Bolts / nuts. Tomaytos / tomartos. Looks like you are all good with the removal, just some semantic confusion regarding removing nuts to reveal bolts.

 

I got the carburetor off and I'm in the process of taking it apart and cleaning, etc. I recall reading sometime ago that the carburetor rebuild kits are garbage, is that still true, or can I use one?

Thanks for providing that picture, it was helpful to me.

 

[QUOTE=hcaulfield57;12608009]I got the carburetor off and I'm in the process of taking it apart and cleaning, etc. I recall reading sometime ago that the carburetor rebuild kits are garbage, is that still true, or can I use one?

Defn reuse the original needles and needle seats. Don’t use the new ones even if provided in the kit. Learned that one the hard way.

 

Carb rebuild kits are fine. Just don't use their float needles and seats. If your float levels were fine there is no reason to adjust them. Always reuse the old needle and seat. Don't use any gaskets on the black plastic plate. Clean it with brake clean. I like to put a thin coat of black rtv on the plate. To make sure there's no vacuum leaks.

 

I'm in the process of putting the carburetor back together. I took all the throttle linkage parts off of the spindle that connects them to the throttle body (sort of regretting it, but I think I have it reassembled correctly). Is there any sort of grease or lubricant that should be placed on the spindle? I haven't used any sealant on any of the gaskets and I'm just tightening things similar to how tight they were when I took them off. Does that sound right?