85rx7gslblack

So I have been going back and forth between a vacuum leak, fuel pump and carb issue. I think I have concluded the carb issue, but I will post a picture and ask one question before I dig in an learn how to do this.

Again, this is a 1985 RX7 GSL 12A Engine all original with 71,500 miles. Tonight after starting it and getting it to run long enough, I was able to take off the air cleaner and only see fuel coming from the top right injector in the picture. There is nothing coming out of the top left injector, and if I remember correctly, nothing comes out of the bottom two injectors until you get up to speed or a certain RPM?

So just to verify, on startup with the choke pulled out, I should be seeing fuel coming into the top two ports (in the picture).

As you can see, despite a moderate dose of carburetor cleaner, and fresh 91 octane gas with seafoam in the tank last weekend, I believe I am at the point of removing the carb, getting the good kit from say autozone and spending next weekend reading, cleaning and rebuilding. Thanks in advance for any insight.

junkyard racer

There is a TON of info on this site. I say go buy a new ink cartridge and a ream of paper and print out a bunch of threads. Also, check out sterlings website http://sterlingmetalworks.com/

Another option would be to send him your carb and get a "sterling" back in return. Its somewhat of a cheap option and probably one of the better options in the long run...

85rx7gslblack

Well, I downloaded and printed out the shop manuals, and did quite a bit of reading on the sterling website.
I went a little crazy last night, removed the two fuel inlet bolts, cleaned them and the screens. Which brought up another question about the alignment of the holes in those bolts, but I will start another thread with pictures for that.
Then after it still wouldn't idle / run, I went another step and removed them again and blew air through the system which proved that one primary and both secondary nozzles/injectors are delivering fuel to the carb, just the one is plugged. Of course then I had to get the excess fuel out of the carb and pull the plugs.
Although, I now have a rebuild kit for the carb, with the other things left to do, I think I am going to send it to Sterling, but I'm giving it until the weekend when I remove it to decide.
On other thing I am contemplating is trying to remove just the air horn and see if I could get that one primary nozzle clean, but we'll see how much of a project that is.

Oneiros

Sounds like one of the jets is blocked, either the primary main jet or the primary idle/transition jet. Does it idle poorly but run fine once the throttle is open? Or run poorly at both idle and part throttle?

85rx7gslblack

So, it starts pretty good cold with full choke, it then trys to idle down and starts hunting. With full choke I run about 1500 RPMs. In the past, it would run around 3000 RPMs or more on full choke, but I am assuming now that is because one of the primary jets is plugged.
With the new gas and seafoam, I can now give some partial throttle with full choke and it runs pretty steady at 3000 RPM.
After it warms up, it gets much harder to start, and if I get it up to temperature where the choke pulls in it is almost impossible to start.
During the warm up period with full choke and partial throttle to bring it up to 3000 RPM, it I let off of the throttle at all at that point, it will just die.
Just an FYI, I have gone through all the other stuff like checking all four spark plugs, timing both leading and trailing igniters, etc

DivinDriver

iTrader: (15)

Working on an open carb that's still bolted to the intake requires you be very, very careful that nothing small escapes down the intake, or into invisible/inaccessible recesses on the engine, or goes bouncing across the floor. Check ***** and such are famous for this, and can be very difficult to get replacements for.

While fighting with grumpy float levels, I set my carb up so that it's a little easier to pull the air horn without demounting the carb (switched the cotter pins to hairpin-style, etc) but if I have to go further than that, like pulling rear jets, removing the carb is just easier and safer.

The back jets and linkage that face the firewall are a real bear to work on while the carb is still on the car. The risk of losing things or of mis-threading a jet is pretty high due to the angle you have to work at.

Kentetsu

Pull the fuel jets and you will probably find that at least one of them is clogged. There is a fairly easy way to do this:

1. Remove the brass plugs from the front and rear of the carb.
2. Reach in with a small screwdriver and loosen both jets at each end of the carb (don't remove them yet).
3. Once they are loosened, reach in with a wooden toothpick, jam it into the jet, and use that to finish unscrewing and removing the jets.
4. Clean them out with something that won't damage them, removing all signs of crud.
5. Installation is simply a reversal of this procedure.

I went through exactly the same thing. She would run pretty good as long as the choke was on, but after that, the more gas I gave her the worse she would run. That's because there was not enough fuel making it through the jets.



.

85rx7gslblack

Boy, did I get a surprise tonight, after about an hour or so of removing hoses and couple of rusted bolts. I was able to remove the air horn. Hopefully I will remember where everything goes at the end of the weekend.
Anyway, look at the attached photo with all the dirt I found. I cannot believe any of the injectors were actually working. Both bowls were filled with debris and dirt.
I spent another hour of carefully cleaning the bowls and around the carburetor with q-tips, paper towels and carb cleaner. I still have quite a bit of cleaning to do, especially to whatever I can get to around the outside with the air horn off.
I will try to remove the jet that I know is plugged on Saturday per Kentetsu's advice/procedure (by the way, thanks!)
After I do the one that is plugged, I will decide if I will attempt the others, as they appear to be working from what I had previously determined.
So the only question before the weekend, is I looked in the rebuild kit I have and there is another paper gasket in this kit. Did I read correctly that other kits have a metalized one that goes between the air horn and the throttle body? Obviously, I am concerned with the amount of dirt I found that had entered the carb, but I may have caused that myself when I originally cleaned the engine compartment a couple of years ago.

Kentetsu

I'd consider getting a paint can full of carb cleaner and soaking the hell out of that carb. That will give you the best chance of getting all the crud out, because the crud you can see is only a small part of what's really going on inside that carb.

Do yourself a favor and pull/clean all four of the jets. Its easier to make sure they are clear than to guess and have to do it all again later.

Paper gaskets are the norm.

Good luck.

Oneiros

Yeah looking at that I wouldn't do anything less than rebuilding and cleaning it entirely. It's not a big job and will save you time in the long run considering if you dont do it properly things will clog up again later on.

85rx7gslblack

So Thursday, Friday Night and Saturday morning. The Air horn and top of the throttle body are clean, and the car is running! Many q-tips and tooth picks, and a another can of carb cleaner and on a very short ride, so far so good. Time to register, get it inspected and have some fun!

Oneiros

good stuff that is looking a lot nicer.