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Gas pouring into the venturis in the carb; replacing my '82 carb with one from an '86
I have an '82 RX& GSL with about 62,000 miles.
It has had a small leak around the carb that I have been working around by using starter fluid (I start it every month or two and drive it around the neighborhood).
This past week I tried to start it by, turning on the fuel pump for 30 seconds or so, pull out the choke, spraying in some starter fluid and cranking it up. This sequence has worked for the past year.
However this time, it cranked a couple of times, then stopped. Also, the choke seemed to pull out with less resistance than usual (I know it is a magnetic release, maybe it pulled out easier as it was energized by the switch being in the run position).
I got out (with the fuel pump still running) to inspect the carb and discovered that the venturis were filled with gas and it was still pouring in.
Am guessing it stopping cranking because the chambers were will with fluid (gas) and doesn't like trying to compress that..
Anyone ever seen this kind of carb failure? I am not sure how the gas is getting into the venturis: could it be bypassing the jets? The leak I observed prior to this was on the outside of the carb.
Also, I have a potential angle on an '85 carb: will it work on an '82?
Advice on how to proceed would be most appreciated.
First thing is to get all the fuel out. Remove the coil wire at the coil. Make sure the plug wires are away from the spark plug holes (lay on top of engine). Remove the spark plug and place a big towle in front of the plug openings. Now crank the engine get the gas is out of the chambers. Change the oil after you know it's going to run but not yet. Probably a stuck needle or trash preventing the needle from closing. Try tapping on the carb with a screwdriver handle.
Hook everything back up and see if it will fire up and not leak fuel. At this point you can also put some SeaFoam or carb cleaner down every opening in the top of the carb. I once used a whole can of carb cleaner to get a needle unstuck. it worked great and did not have to do a rebuild.
Once you get it running for a few seconds, change the oil. It's got to be full of gas.
Last edited by KansasCityREPU; Nov 8, 2022 at 09:10 AM.
Stuck needle would make sense and sounds like you've been there, done that and gotten the t-shirt.
And gas definitely got in the oil? (guess that how the whole apex seal thing works.
It freaked me out so much that I didn't take the opportunity to see if it was filling just one venturi then spilling over to the other three.
As I mentioned it had already been leaking elsewhere on the outside (a drip, drip) and on a different post several months ago, someone said that could be why I needed starter fluid to get it going.
So going to probably go for a rebuild.
What about the carb on a 1985 engine (13B) -- is it plug-and-play with a 1982 12A?
The 1985 13B is not carbed. It's EFI and will not fit. However, a 1985 12A carb will work. There are small differences but nothing that can't be made to work.
If you do decide to rebuild, there are many-many threads on what NOT to do and how to tackle it.
I'm not a carb expert, and it probably shows. I've experienced your exact issue were the gas was overflowing from every opening on top the carb. I know the "OH ****" feeling of turn it off. It was my 80 years old dad that suggested some carb cleaner. I was hesitant but gave it a go and it worked. Used a whole can and sprayed it in every opening on the top of the carb. Let it sit over night. Came out the next day it it ran like a champ. Then I changed the oil.
Rotary engines are no different in respect that it uses oil to lubricate. Gas washes away the oil and just drains into the pan like the oil does. At this point the oil is so thin it can't lubricate.
And DONT throw away the needles and seats from the existing carb. Found out the hard way that those that come with the rebuild kits almost universally stick. Best practice is to clean and reuse the existing ones. Just went through the same thing as yourself and it was hell for a while... several weeks of trying all sorts of things but finally got it running reliably. Once the carb is rebuilt let us know and I'll chime in with some things I learned.
For my rebuild I used an Atkins rebuild kit. you will also need a complete carb spacer as you cannot replace just the gasket on the spacer. Google ‘Atkins FB carb spacer ‘ and it pops right up. Not cheap though.
Also spent a lot of time watching and rewatching the RAD Potential video that I have screenshot below. It’s not a step by step, and I did not find a step by step video elsewhere, but is the best guide I could find. Others
may have one to point you at.
Copy the little carb stand the guy uses in the video. It’s very simple and can be made from scraps. Makes the job soooooo much easier.
By far the most useful thing I did was take a whole bunch of pics of the carb from every direction, plus several videos panning around the carb. Even more important was I took a picture of EVERY piece or screw I removed BEFORE I removed it, using a screwdriver to point at the part I was indicating. I then put the removed part in its own ziploc bag and wrote the phone time stamp on the bag so I could match the part to photo. Was much easier than making up descriptive names to write on the bags then forgetting what you meant by ‘thing that attaches above the other thing’ a week later. I then put the bags vertical in a box vertically in the order the parts were removed. Made reassembly relatively easy as could just reverse the photos and match the time stamps to the bags.
Lastly I would recommend concentrating on cleaning the jets and bowls, and rebuilding the accelerator pump. Leave all the linkages where the accelerator, choke, OMP etc in place as much as possible. That way you don’t risk introducing more problems.
If you go ahead, let us know when you get to the point of putting back in the floats and needles. There are very particular dimensions you need to set for the float heights. Again, not hard but I learned the dimensions were important the hard way!
Beware, I am a novice at this. There are people like Kansas on this site that know waaaaay more than me. But I did just fix pretty much the exact problem you had and hopefully can talk you around some holes I fell in.
As far as the carb spacer goes you can reuse it. Don’t try to replace the gasket since it is glued on but it likely won’t leak. It’s expensive enough that I would try it, and only replace it if it’s leaking.
Just had a thought. Where is the original small leak you mentioned? If only addressing sticky needles and a leak higher up in the carb maybe you can get away with removing just the top portion of the carb? You could leave the lower portion in place so you don’t have to deal with the carb spacer.
Digging around on this site showed a wide spectrum of opinion on reusing existing carb spacer and it’s none-removable gasket…. But I am fortunate to have cash set aside for the work so bought a new one.
This thing looks a tad bit more complicated than the motorcycle carbs I have been working on lately.
No idea whether there were any fuel system mods prior to my ownership: picked this car up off of BAT 4-5 years ago, have put less than 1,000 miles on it since.
But looked at the fuel pump and it seems stock, i.e., not some universal replacement.
Re. the leak I had before this, it's in this thread with a video of the drip-drip. Since that leak started, I've had to use starter fluid to get 'er going.
I assume that the $100ish rebuild kit will get me everything I need except possible the carb spacer? It looks like it even comes with an accelerator pump diaphragm.
Slow_Sevens, when I get to the floats in putting it all back together, I will definitely reach out.
Yes the Atkins kit I got included everything, even the accelerator pump diaphragm. But not the carb spacer/gasket. That diaphragm was the cause of my rebuild. The diaphragm has stiffened to boot leather and if I blipped the accelerator there was not enough squirt of gas from the pump and the car would die. That was a pretty easy fix… but in fixing the accelerator pump I let the gremlins into the floats and needles and that was so hellish a repair that when I briefly set the car in fire (keep those plugs away from the spark plug holes when deflooding!) I briefly considered just letting her burn.
You will actually enjoy rebuilding the carb. Sitting at a bench in a warm workshop with your music and coffee beats wrecking your back bent over the engine bay.
