My exhaust is getting red,,, realy hot
 

Like many here i have Nikki problems (1985 SA2 12A Euro version, so i take some time to clean the link´s and outside moving parts from the carb with break cleaner spray ( it was the best that i have on that moment).

After put all togheter engine start and all goes fine, except that i notice the pipe
just after the reaction chamber start to go red, realy hot, like i was reving the engine to the limits, but that car was stoped and only at about 750rpm IDLE.

I have check the spark plugs and they have too much carbon, like 10.k or more and i know that i have clean it 100 miles ago, so i assume it is running too rich.

The car run like a 50hp and if i push over 4k RPM it backfire

I´m checking the manual for Nikki to see if i can understand better this carb.


Any ideas that can help?

tanks in advamce

Before digging into the carb, start with a couple of easier checks just to eliminate some more likely possibilities.

1. Verify that you still have spark on the leading (lower) plugs.
2. Verify that the timing is correct (not retarded).

9 times out of 10, glowing exhaust is due to an ignition issue. Either of the two things mentioned above would result in a late spark, which means late combustion, which means all that flame and power potential shooting into your exhaust system rather than making power in the motor.

:)

your timing sounds like it's way too retarded. check your timing.

Yes, i was going to check it today, but my friend was not there, so i have to check it later.

I have look at the advance lines, the strange is that they have no valves, it looks they run direct, this car is mine for short time, so i´m still fixing it litle by litle.

On top of engine i think that i have only 2 solenoid (someone before may have remove some stuff)

I think that the carb also need to be checked, once i notice the front secondary was letting fuel pass direct (like something was cloged) and fload the plugs 2 times.

I have to buy a timing light for this situations, and also install a wide band sensor

Most important thing right now, see if you still have spark on the leading plugs.

Also, lots of carb info at www.sterlingmetalworks.com He even has a forum if you have questions www.sterlingmetalworks.com\bymc

He is the God of stock carbs, so you can get advice straight from the horse's mouth. :)



.

also, if you are so inclined, run a compression test and check carb settings...

Yes, the leading are working, i have disconect the trailing and the engine still starts and run, also at same time i check that the trailing have spark.

Could it be also one appex?

Okay, you have spark so now you need to confirm the timing...

Hello, could you or someone tell me how to check if my distributor is in correct place?

I have many manual, but still didn´t find how to set it or verify, i know that the timing mark must be on top of the pulley but the dizzy i don´t know is correct position.

tanks in advance.

Would a vacuum leak cause the exhaust to get red hot...?

I just changed the hose that goes from right above the exhaust on the lower intake manifold to the carb / aircleaner. What a difference that made.

It wasn't dryed out and cracked so bad... Just enough to give me a handful of problems. Like my idle was bouncing ever so slightly as if the motor was ported, but she ran good or so I thought. She was giving me hard starts on cold mornings. Glowing header on the rear rotor... Can't hurt ot check it.

Before i do have vacuum leak (and it was big) the connection to the crank was not in place, the valve was damage and the hose was just standing on the engine.

After i replace that the rpm goes from 1100 to 600 or 700rpm at idle, now i start to think that maybe someone have adjust the carb for this tipe of condiction, and now it need to be adjusted again, or something more seriouse need to be done.

If you're glowing on the rear only, then that is different. Could be shutter valve stuck closed causing a lean condition.... Maybe a stuck float, or a couple of other things I can't think of late at night while I'm falling asleep at the keyboard.. :)

clogged cats

^^ thats what i was thinking. makes sense since you mention loss of power and the red glow this way

I don´t know if is on the rear, because the exhaust is original and the glow is right after the react chamber were the pipe starts and is tinny, so is the first place to glow.

I will check also the shutter valve.

The last thing that i drive with carbs was my old toyota corola (l16 years ago), so i have to learn again and make this engine works.

clogged cats,,,

yes could be that also, but to remove it i think that i have also to rip out all related parts, and i´m still looking for headers or complet system to replace.

And that i can only order it from USA or ask someone to make it here (costume exhaust).

Ok, so i did found one problem.

Take a good look at the windows to check levels, the back one (checked with a mirror) is right on the center, the front one is way up, since i didn´t touch inside the carb is possible that something just bend or come out of possition?.

Is it possible to repair this only by removint the top of the carb?


Also get a timing light, T and L are in different places but still near center, so this must be a rich condiction based on the level of front barrel (don´t know exact name).

Just need to know the best way to fix it

Yea but that hose goes into the lower intake on the backside, meaning towards the firewall side, which is the runner for the rear rotor. And if a lean condition causes the header to glow... I'm not really too sure that's what I was actually asking... It might make the whole exhaust manifold glow b/c he doesn't have a header where the pipes are seperated front to rear rotor... everything mashes into one. Again I'm could be wrong. I'm still figuring all this out myself.

Okay, so your front float bowl is too full. Could be a stuck float, not cutting off the fuel flow as required. Try banging on the carb with a plastic hammer or something similar that won't cause damage to see if you can shake it loose. Otherwise, pull the top of the carb off and get to work. :)

Yes, i have try that some time ago after the engine fload 2 times, it was soo bad that fuel was coming out of the secondary jet.

so today i have also try it with a ruber (plastic) hammer at same time it was on idle, still didn´t move from top.


So i´m going to take the top of the carb, since here there is no repair kit or any gasket for this carb (or any other part in a range of 4000 milles) will i need to replace this gasket?.


How about to remove only the window and try to play with it inside to get it lose?


2 things for this engine----

1-No solenoide valves for vacuum advance (they are direct with vac there all the time) can the engine run normal like this?

2- No shutter valve, i know that people remove it so this is not a problem, but make me think that this version is different from some i have see here on the forum.

I can say that i don´t have rats nest, but i still have airpump (with hoses connected) still have cat´s and a strange pipe that goes from near engine exhaust and comes out near the rear muffler.

On the top of the engine there is only 2 valves, one is small the other one is big and connected to the filter ( i think is the fast idle or something).

I will post some pictures later

Here some pics of it-

The level is like red line in picture
http://memimage.cardomain.com/ride_i...0026_large.jpg

and here is the 2 only valves on top of engine

http://memimage.cardomain.com/ride_i...0028_large.jpg

Some more wrong things in this carb.

The power valve (richer solenoid) was wrong, imagine that the pin was pointing inside the valve, and passing inside the litle coil.

So it was not blocking the air passage as it should do.


Sorry this question but i´m still learning, in what way this power valve afect the engine if placed wrong?

My imagination tell me that maybe is the cause of burn too much rich.

I have also open the glass window and play a litle up and down with the float place it again and it looks is stays lower, maybe not the same as the back one, but also not on top.

tomorrow i will try to ride it and see how it looks.

Okay,,,

For a mountain of information on these carbs, and how everything works: www.sterlingmetalworks.com Sterling's site is like a frigging library...

Ask Sterling himself for assistance here: www.sterlingmetalworks.com\bymc

Or you can wait and see if he shows up here... :)

Update.


Today i manage it to idle without the exhaust glow.

I just play with the screw that is protected (anti-tamper) close it and the exhaust act like normal at idle, but over 1000 it starts to glow again.

I remember that this problem only starts after i stop the vacuum entry that was big (were the crank hose connects), since i don´t know much about the pass of this car i start to think that maybe someone may have setup/tune the carb based on the extra air that was coming from the hose to the base of the carb, and that person may have by mistake change air/misture, fuel and other things.

With this settings the car is smoth at idle, runs a litle better and the backfire if i rev over 3500rpm are 1/2 laud as it was before, but still not that machine that goes to 6500 or 7000rpm in 2 or 3 gear.

Any opinions on the best way to tune this carb? were to start.

I do have manual´s and have read a lot (at least i try) about this carb and engine, but if any of you have better experience and could give me the better and fast way to do it, it will be better.

Tank you in advance to all of you that have give me ideas on what to check after this problems start, i hoppe that in short time i see the car running at least as it was stock.

After some time looking i will try this- http://www.sterlingmetalworks.com/idle_tuning.htm
i have open the web many times, but didn´t notice that there was the Idle Tunning.

9 Easy Steps to Idle Tuning:



Step 1. Adjust the Deceleration Dashpot and the AC Idle Compensation Valve so that they are not interfering with the primary throttle operation.
Step 2. Open primary valves to use the main primary circuit to get your car running by turning the Idle Speed screw in.
Step 3. Set the Fuel Mixture screw to 2½ turns out from closed. (Never bear down on this screw to tighten!)
Step 4. Set the Air Screw to 2 turns out from closed. (if you have one on your carburetor.)
Step 5. Start the engine, reduce the engine RPM using the Idle Speed screw, and let it warm up.
Step 6. Turn the Idle Speed screw in until the engine almost shuts off. (This will lower the engine RPM.)
Step 7. Turn the Idle Mixture screw in, in ¼ turn increments, waiting 2 seconds after each change, until the engine starts to skip. (This will raise the engine RPM.)
Step 8. Repeat steps 5 & 6 until the desired idle speed is achieved. (Usually this is between 750 & 850 RPM.)
Step 9. Back the Fuel Mixture screw out less than ¼ turn to ensure that the idle is not too lean. (This may require readjusting the Idle Speed screw first.)


My carb is a 1979 1980 so i have to deal with fuel and air misture screw, tanks sterling for all the details

Shouldn't Step 8 read "Repeat steps 6 & 7," rather than "5 & 6"?

Yes, it should. I have fired my editor.

Impossible to tune.

It didn´t tune so i start to look inside the carb wille it was running, move the accelerator by hand and notice that every time the engine crank different there was a lot of fuel comming out from here, red arrow.


http://memimage.cardomain.com/ride_i...0042_large.jpg

I still didn´t see the cause, but any ideas for the reazon that it was droping fuel as a crazy?



So i take it out and here is some picts for you just to see how "clean"
this carb was.

http://memimage.cardomain.com/ride_i...0041_large.jpg

http://memimage.cardomain.com/ride_i...0035_large.jpg



This is a picture from the back level, engine stop
http://memimage.cardomain.com/ride_i...0034_large.jpg



And this is the front one , more close to center after i play with it.


http://memimage.cardomain.com/ride_i...0036_large.jpg



after i removed the carb, most of the one i have see in the forum are only open
in one side, this one is like you see, don´t know if is better or not.
http://memimage.cardomain.com/ride_i...0032_large.jpg



Close shoot of the intake


http://memimage.cardomain.com/ride_i...0031_large.jpg



How about porting at least the center ones? too much closed what do you think?

http://memimage.cardomain.com/ride_i...0029_large.jpg



More pictures of my car here http://www.cardomain.com/ride/3254885/3

Sterling, please tell me, based on the windows pictures, they are high correct ?

The level line should be on each side right on the mark ? that V that we see means is too high?

I think it should be one single horizontal line!

One more thing that i need to adjust is the "primary throttle valve initial opening angle" , as it is soo close that i almost can´t see the light pass, i´m going to try make it like manual says, 0,05mm (0,002 in ), still one side looks more open then the other.

Your bowl levels look fine, but the primaries look to be too far open.

Ok tanks.

About the primaries no, i was taking it apart so the coil was not there, thats the reason they are open on that photo.

Like i say in last post they were too close, i have set it at 002 in, it was a litle adjust but now the gap is there.

I check the 2 weigth and the 2 ball´s, all were in place

I have to made the gasket by hand, don´t know if it will work.

If anyone have suggestions about this rebuild, just put it out. most of this things are new for me.

By the way, the weigth one the acel pump is very small compared to the other one.

It is as large as the ball, if not less, and is like dacing because it is tinny.

Could this also cause dripping gas on the back primary at idle ?

No.

The richer solenoid must be properly assembled. If it is not, then there will be a direct air route that goes from the very top of the fuel bowl at the front of the car down through the main body of the carburetor and throttle body to a port in the opposite diagonal primary bore in the cast steel throttle body.
The fuel bowls have to have a vent in order to work. Since the vent acting on the fuel bowls is much larger than the port from which the richer solenoid circuit can cause a vacuum leak, it is unclear at what engine RPM the throttle-body / manifold vacuum demand would over-power it and begin to effect the atmospheric pressure acting on the fuel in the bowls.
I suspect this could happen when the engine is revved beyond about 4000 RPM, but I'm not sure. If and when this occurs, it could cause a temporary flooding issue, but it should effect both floats evenly. When they return to normal, one may be hung up sometimes... But that part is all speculation.
However, the presence of the vacuum leak to the rear rotor is definite in this scenario. I have come across this when people strip the Nikki and do a good job of blocking all of the external ports, but fail to completely block all internal ports to the richer solenoid circuit.

The correct way to install the richer circuit components is to remove everything and install the solenoid first. then install the weight, cap screw & jet. Be sure the spring is inside the solenoid before the piston. You can also remove only the solenoid, simply flip the carburetor over so the weight falls toward the top, and screw the solenoid back in.
There is no check ball.

Some more pics.

It is a slow work because i don´t have much time, today i take out the
exhaust to clean some extra pipes inside, the suppose cat was strange because
there was only one pipe inside, it was not like actual cats, will post some pictures
later.

since it was out, i want it to be painted and clean.

http://memimage.cardomain.com/ride_i...0044_large.jpg

http://memimage.cardomain.com/ride_i...0048_large.jpg



i hoppe i did it correct

http://memimage.cardomain.com/ride_i...0045_large.jpg


Something is telling me to clean also the engine

http://memimage.cardomain.com/ride_i...0043_large.jpg

Exhaust output

http://memimage.cardomain.com/ride_i...0046_large.jpg

http://memimage.cardomain.com/ride_i...0047_large.jpg

I suspect using a flat feeler gauge will give you too much initial opening... supposed to be set with a wire guage, so you are measuring the opening only at it's widest point.

I personally have never been able to find a small enough wire guage, so I use a dial indicator on a magnetic base, with the tip right against the top of the butterfly arc, which seems to work OK.

http://img.photobucket.com/albums/v2...f/IMG_0051.jpg

How did you do it?

set it to 0 and than open till it goes inside that 2 marks?

I also have that dial indicator and the base, since the carb is still out i will check it later.

Tanks for the ideia

I set the gauge tip against the side of the butterfly that comes 'out' from the bottom, loosened the carb adjusting screw so the butterfly was fully closed, zeroed the dial, and adjusted the screw until the dial gave the specified opening in thousandths. I think the US spec was less than 0.002", but don't remember exactly - - was several months ago.

Since I had the dial guage set at the same angle that the butterfly inititally moves in it's rotation (instead of straight up) and it was touching the very tip, there's no significant trigonometric error; valve motion equals opened distance. Motion on either side of the butterfly is symmetrical, so the opening distance is equal regardless of which side you measure.

It worked out well enough that the car started on the first turnover, and later, passed California smog tests.

Finaly got it runing

this was the first try to run it

http://www.youtube.com/watch?v=cUfQw9lDLy0


And here idle at normal temp, after i change to electrical fun the temp meter is in
vertical, before it was lower.

http://www.youtube.com/watch?v=p1t_aOYIVyw

Still neet to go adjust the smog (co2) and full test it on the road, but for the moment is much better.

Tanks to everyone that replay and give ideias for this, and now my exhaust is not getting red anymore

Congratulations!

Tanks DivinDriver, but the problems didn´t end yet.

The glow exhaust is no more, but the carb is still not ok.

now that i adjust the initial angle there is fuel coming from the 2 centers at the top, i go to check the CO2 make it run in acceptable level but notice that sometimes the CO2 go high, check the top of the carb and there it was, fuel droping like crazy again.

There is suppose to be a place were the air pass if the engine is at idle, because i didn´t have this main problem before i repair the breack hose that was conecting the crank venting.

Later i´m going to make it work as it was before, same vacuum in same place.

In general the car is must better, run better and don´t backfire laud as it was before if i rev over 4000 rpm and change gear, but still not that engine with 100hp looks more a 70hp or less, the fuel filter is new (the first thing that i was able to buy for this car here, and that is because there is some Hyundai that use it also).


I consider going EFI in short time, maybe Megasquirst

If the mixture was adjusted previously with a big vacuum leak, you'd be running rich now. You have your initial angle adjusted, but now you have to adjust your idle mixture.

Are your bowl levels still correct?

Yes, that was one of the things i have check and double check many times during
the time i was trying to adjust it on the co2 machine.


I notice one thing in this engine, don´t know if any of you have this setup.

There are 2 hoses connected to the crank, one comes from the filter, the other comes from a vacuum connection, right there under the carb, this vacuum
connection use to have one ball and one spring, this makes air pass only in
one direction, the spring still was there but the ball never find it, so i get one of
the same size to fit there.

So the function of this is to make the air coming from the air filter pass on the top of the crank removes any vapor oil etc and send it inside the engine, and this was a permanent air input that i have repair and later block it permanent, leaving only
one connection to the top of the air filter, i´m going to restore this.

But still no reason for the low power over 4000rpm, and a good reason for it to suc more air from the top of the cab making it drop some fuel

The vacuum line you describe from the air box to the crank case, then case to intake check valve is the pcv system. Plumb it as you described. Either repair your valve with a new ball, or get a pcv valve for something else.

The dripping you get from the primaries is fuel being pumped past the bowl inlet valves. You don't want that dripping. Either the float is not closing the valves well enough, or the valve is toast. That is easy to inspect if you remove the top of the carb again.

Also confirm the fuel return line is free flowing. There is a check valve in-line as it heads back to the fire wall.

At 3k RPM the CO2 is ok, so this must be related to PCV valve not working, making too much vacuum to pass from the primaries and suck fuel with it inside the engine.

If you see the first video it looks that it start very easy, but before that i have to crank the engine without spark plugs several times in order to have fuel on level,
i have also pump some compressed air to the tank because it was not coming only with the pump, i have replace the fuel filter so maybe the lines drain all fuel and it takes time to refull it.

Now, about the fuel pump, if we are cracking the engine, should not be a constant flow of fuel?
I notice that if i crank only for 1 second and stop the fuel coming from the line was the same quantitie as if 5 seconds of cranking, it this nornal?

Hello,

after many modifications my 12A end with some extra parts.

Megasquirt, CBR600RR ITB´s with air filter and 8 injectors, i have also made the Headers, and intake.

https://www.rx7club.com/megasquirt-f...my-12a-835786/


Some more fine tune to finish, but it runs every day.

Tanks to all that have help me.

The car is getting fun now.