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Thanks! Comparing it to my diagram its identical so I know mine is reliable. I was just confused by the fact that my hoses were put on wrong, and I was thinking I was reading it wrong. By the way, any issues running royal purple 75w90 in the transmission? It has friction modifier additives for an LSD, but it also claims its safe for synchronized transmissions. Is that true?
I used Royal Purple, but don’t remember if it was a particular weight or additive. I do remember finding threads here that gave recommendations, and following those. I also found that a Google search with ‘RX7club’ included in the search bar yielded better results than the search function on RX7club itself,… which I have never been able to master.
Yeah, searching through the site itself has proven difficult. 75w90 is the sae 90 fluid royal purple sells, so im pretty sure its the one most people use for the transmission.
I used Royal Purple, but don’t remember if it was a particular weight or additive. I do remember finding threads here that gave recommendations, and following those. I also found that a Google search with ‘RX7club’ included in the search bar yielded better results than the search function on RX7club itself,… which I have never been able to master.
Alright, good to know! Still have not gotten to a compression test yet, and still trying to wrap my head around the wiring of the coils and why its flipped.
Update: It will not idle anymore! After it is no longer choked it just kinda sputters out. Decided to finaly get a look at the carburetor while it was running and im prettu sure only one barrel is getting fuel. From what i saw the front primary barrel was just dry while it was choked, and from the moistness around the carburetor I think im looking at a rebuild sometime soon.Will do a compression test hopefully tomorrow, but any suggestions on what to do carburetor wise?
Can you see where the dampness you see around the carb area is coming from? Maybe just need a gasket rather than getting into a full rebuild?
But before rebuilding do a quick check to make sure the issue is in the carb, and not a simpler issue like a fuel pump, filter or fuel line issue.
To check… start the car, then let it die. Then check the fuel level in the windows of both fuel bowls. The front window is the easiest to see, and look for the fuel level to be half way up the window. I had to rock the car so I could see the top of the fuel moving. The rear window is hard to see. I ended up using a dental mirror and flash light. If both bowls show fuel half way up window then work on the carb.
To get an idea of what you are in for watch this video. Sadly not a step by step, but an excellent intro. And DEFINITELY build yourself a little work base like in the video, takes 5 mins and saves a lot of frustration. Too old to work out how to post an actual link but Google ‘RADpotential 12a RX7 Nikki carb rebuild’ and if a 56 minute YouTube vid pops up you have the right one.
The hard copy factory manual I have has step by step rebuild instructions. Let me know if I should screenshot you the pages. I also believe the downloadable Fox manual link posted earlier has a step by step.
MOST important. Do NOT lose or
throw away the original float needles and needle seats. Assuming they are original they are the best there is. Aftermarket replacements are troublesome in the extreme, and almost led me to abandon my car!
Lastly a carb rebuild is actually kind of fun. You can do it at a bench, sitting down, playing your favorite music and drinking an adult beverage. My kid equated it to building model aircraft… see pic.
The dampness is sort of just everywhere. All around that bottom area of the carb is always damp. Ive done fuel filters already, have a pre pump and pre carb filter setup. That fuel level test has peaked my interest, ill have to do it later tomorrow and see where it gets me! Im assuming with the way my old fuel filter looked ive got some sediment in the bowls, and nothing is coming from that front barrel so if it does end up being low / no fuel in the front how should I tackle that?
Dampness below the carb could be fuel or coolant. Can you tell by color, if your coolant has one of the typical bright colors? Or try adding a UV coolant dye to your coolant and see if the leaking fluid glows under UV light.
- If its fuel its probably from a bad gasket in the carb assembly, or from a bowl overflowing due to a stuck float needle. You can get an idea of where the gaskets are by looking at the Atkins rebuild kit here https://www.atkinsrotary.com/79-85-1...1-99-131-.html. If its overflow, you should see one or both bowls fill above the glass windows, and be able to see fuel on the top of the carb if you remove the air cleaner and the fuel pump is running. Sounds like you had the opposite problem though, with one primary showing no gas? Mine was a stuck needle and looked like Niagra Falls!
- If its coolant its probably from the O ring between intake manifold and housing that seals where coolant enters the housing. There are two coolant ports, one in each housing, and they are sealed with an O ring when the the manifold is attached to the engine.
On the fuel level test, its a really useful indicator to where your issue is. If looking through the window shows you bowl is empty or too full, your problem is upstream of the bowls... Needles, seats, fuel lines, none-return, fuel pump etc. If the bowls are full to mid way up the window, then problem is downstream of the bowls... inside the carb itself.
Let us know what you find out. I am really good with the upstream part having wrestled with overflowing bowls for months! I am not expert with the carb itself having only rebuilt one. But there are folks on this board who have REALLY advanced carb skills and are very helpful.
Since its not a good time to start it im going to wait till tomorrow, missing exhaust bits and im in a high density neighborhood. Just lettting the fuel pump go it looks like it just filled all the way up, or was completlry empty. Its really hard to see so I will give it a shot with my borescope camera pointing at it next time. The rear sight glass was very damp and so was everything around it, maybe thats an issue? Ill try to get some pictures soon. Is there any possibility something just needs to be adjusted? Hopefully not something tach related since im missing a tach reading...
Yup, seeing the top of the fuel in those windows is a complete bugger. Really hard, especially the rear one. I used my phone, a dental mirror and a flashlight. A borescope is an excellent idea. Shake / rock the car when looking as I found if I could get the fuel sloshing around it was easier to see its top edge in the window.
If you have fluid on the outside of the carb, as high up as the outside of the fuel bowl windows, then its almost certainly fuel as don't think the coolant leak could end up there. In which case, the fuel leak has to be fixed, and hopefully it is also the cause of your lack of idle and rough running and all is hunky dory once fixed.. It was in my case... and it was a total horror to diagnose and fix. Hence my wanting to help. Would love to help someone not go through what I went through. My car now runs GREAT and I want to help get you there. I also had an engine bay fire caused by fuel, but that's a different story but a good reason to chase down fuel leaks!
If indeed its a bowl (or bowls) overflowing, then there are two adjustments. Easiest one, and the one that fixed my problem, was adjusting fuel pressure. Do you know what fuel pump is on the car? Can you ID it and establish what pressure it runs at by finding a manual or spec sheet? For mine I installed a Holley fuel pressure regular, and turned it down until the problem went away. Mine works at 2.5 psi. Second adjustment is adjusting the float levels inside the bowls, but that is more alchemy than adjustment so lets not get into that until we know overflowing bowls are actually the problem.
If you just cant work out fuel level in the bowls through the windows, another trick for testing for overfilling of fuel bowls that is quick, does not require taking major things apart or need special tools:
- Remove the air cleaner box from the top of the carb so you can get a good view of the throat of the carb barrels.
- Turn the ignition key to one notch before the starter engages, you should hear the fuel pump turn on and start buzzing/whining continuously.
- Leave the key in that position, go to the fuse box by your left knee and pull the fuel pump fuse. (For my 81 it was the top right fuse, the one mounted vertically versus all the rest which are horizontal). When you pull the fuse the fuel pump should go quiet.
- Start the engine and run it until it dies. Maybe two or three minutes is what it takes. At this point the fuel bowls are empty.
- Find a helper, and show them where the fuse goes. Dont insert at this time.
- Leave the helper by the fuse box, and you go stand with your ear right next to the carb barrels.
- Have the helper reinsert the fuel pump fuse. Listen carefully. You should hear the sound of fuel running passed the needles and into the bowls. Have the helper cycle the fuse in and out a few times so you know the sound of running fuel. Remember engine is NOT running at any time during this test, just the fuel pump.
- Have the helper reinsert the fuse and leave it there. Keep listening. Eventually after a minute or so the sound of running fuel will slowly stop, it sounds like someone slowly shutting off a faucet. If the fuel noise goes quiet then you know that the floats and needles are working and they shut off the fuel correctly.
- If the sound of running fuel does not stop, or even more obviously fuel starts running across the top of the carb and into the barrels, then the needles are stuck and the bowls are overflowing. If the fuel is not stopping, most times you can double-confirm the diagnosis by rapping on the top of the banjo bolt where the fuel line enters the bowl with the handle of a screwdriver. A sharp thwack can often knock a stuck needle loose and the fuel stops flowing. In which case its DEFINITELY sticky needles.
- Repeat from the very beginning several times. Sticking needles are inconsistent. Sometimes they move correctly. Sometimes they stick and fuel overflows. They should move and shut off the fuel EVERY time. Mine would stick once or twice a drive. But each time the car would completely die, usually at 70mph on the freeway with no hard shoulder.
Sticking needlesmight actually explain some of that, because it just randomly stopped idling. I know where the pump is, but it has no mount so it just kind of dangles by the rear axle along with my fuel filter. I did notice today that the top of the carb with the air cleaner off was damp, specificaly above the barrels, which I thought was weird because i had not started it or even tried to in over 24 hours. Just turned on ignition and let the pump kick on. I cant get it started without brake clean, carb clean, or starting fluid so starting the engine and letting it run until it dies may be premature since it will only idle with throttle or choke. If it does change something I am running premix because im unsure of the condition of the OMP at the moment. Mostly focused on getting it to idle and fixing the stripped out rear hub, tach, spedo, and why on earth my leading and trailing need to be swapped at the plugs for it to rev good enough. Will test all of this tomorrow...
Its a bit too hot for me to test all the fuel pump stuff right now, but I will when it cools off. Its about 93 degrees out, but I still got a video of it dying. The first time it starts to die you can hear me give it some gas and it recovers but 2nd time I just let it go. Exhaust overheating light comes on randomly, its on in this video. The front barrel had fuel today but still won't idle.
I didn’t even know I HAD an exhaust temp warning light!
Homework for when it cools down outside. My son just moved with his car to Tempe and is having similar can’t work outside issues.
- Have a real good look at the fuel pump and see if there are any markings on it to allow you to ID what it is, and hence what PSI it is pushing.
- Work out if the fuel bowls are overflowing by looking through the windows, listening to see if the fuel needle fails to close and stop fuel flow, or if fuel floods out the top of the carb. Video of top of carb with air filter removed from start to stall.
- Take a picture of the main pulley so we can advise on how to check timing if you fix the fuel leak issue but the car still runs rough or will not idle.
- Quick and dirty compression test. Video of tester with none- return valve removed, engine cranked with starter for a few seconds. Both front and rear rotor.
It really does sound like mine when the bowls were flooding, sending overflowing fuel down the barrels of the carb and drowning the spark plugs. Car starts with starter fluid, runs ok for a few second then kinda stumbles and stutters to a stall. Symptoms that also match are can be restarted with starter fluid, fuel on outside and top of carb, and symptoms inconsistent/changing over time.
$20 says you have flooding…caused by sticky needles, misadjusted floats or a fuel pump pushing too much psi.
Get your homework done and let us know the results. I added compression test and video of top of carb with air cleaner removed from start to stall… wonder if we will see overflowing fuel draining into barrels.
Got a picture of the crank and what I believe to be timing marks. I will start experiments with the fuel pump and fuel levels today. I keep blanking on getting a compression tester, so hopefully I'll see my note to myself today. Would seafoam do anything to help if needles are sticking? Its got older gas in it.
Got a picture of the crank and what I believe to be timing marks. I will start experiments with the fuel pump and fuel levels today. I keep blanking on getting a compression tester, so hopefully I'll see my note to myself today. Would seafoam do anything to help if needles are sticking? Its got older gas in it.
That looks to be original, with nice clear timing marks. To double check measure the distance between the marks which should be 20mm, and the circumference of the pulley rim where the marks are which should be 320mm. There is a bit of genius in the design of the pulley in that each mm between points on the pulley rim is one degree of rotation. Someone deserves a bonus at Mazda.
sorry, no experience with Seafoam. I have seen many posts about its use for resurrecting an old engine, but if memory serves me right it was for unsticking apex and edge seals?
There is a picture of the fuel pump. I think its missing a mount because it's just dangling there. Also finally got the nylon washers for the horn, so I went to put the fuse back in and it tried to turn over? What? Disconnected battery and plugged in fuse and everything was fine, started good enough. I'm running a relatively high seafoam to fuel ratio through it to see if that helps any. Haven't had time to look at it any further since I've been giving my tow vehicle some love, but tomorrow I will focus on it again!
There is a picture of the fuel pump. I think its missing a mount because it's just dangling there.
Looks like original fuel pump, that has been unbolted. Should be held on by two nuts on other side of panel. Pics from someone selling on eBay that show how it’s mounted.
You prob already found this guy but just in case…. Meet Mr RADPotential. A very useful person. Here is his intro to fuel pump location, wiring and mounting. Could be you are missing the mounting plate. Anyhow… ignore it for now, maybe just zip tie it out of harms way.
I don't believe I have that panel, where does it sit? Both pump and filter just dangle there.
The guard bolts to the underside of the body. The fuel pump attaches to the guard by 2 rubber isolator bushings. The filter goes into a wire spring clip. Otherwise, yes, it all just dangles there.
Yes, I can confirm that mine is missing that. Any advice for a long term solution?
Don’t worry about it for now. See if you can zip tie it out of harms way so you can give time to the carb gas leak / overflow and hard start rough idle issues. Only address the fuel pump problem if you can’t zip tie a quick fix.
Last note on engine was you had it Seafoamed and running. Is it starting without starter fluid? How is idle now? Any fuel leaking around carb?
09-14-23 | 03:37 PM
