RX-S7V7N

Like many here i have Nikki problems (1985 SA2 12A Euro version, so i take some time to clean the linkīs 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

Iīm checking the manual for Nikki to see if i can understand better this carb.


Any ideas that can help?

tanks in advamce

Kentetsu

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.

Hyper4mance2k

iTrader: (40)

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

RX-S7V7N

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 iīm 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

Kentetsu

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.



.

mazdaverx713b

iTrader: (91)

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

RX-S7V7N

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?

Kentetsu

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

RX-S7V7N

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

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

tanks in advance.

85TIIDEVIL

iTrader: (2)

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.

RX-S7V7N

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.

Kentetsu

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..

dominicaneddy

clogged cats

boyee

iTrader: (3)

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

RX-S7V7N

I donīt 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.

RX-S7V7N

clogged cats,,,

yes could be that also, but to remove it i think that i have also to rip out all related parts, and iīm 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).

RX-S7V7N

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 didnīt 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 (donīt know exact name).

Just need to know the best way to fix it

85TIIDEVIL

iTrader: (2)

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.

Kentetsu

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.

RX-S7V7N

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 didnīt move from top.


So iīm 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 donīt have rats nest, but i still have airpump (with hoses connected) still have catīs 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

RX-S7V7N

Here some pics of it-

The level is like red line in picture


and here is the 2 only valves on top of engine

RX-S7V7N

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 iīm 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.

Kentetsu

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...

RX-S7V7N

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 donīt 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 manualīs 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.

RX-S7V7N

After some time looking i will try this- http://www.sterlingmetalworks.com/idle_tuning.htm
i have open the web many times, but didnīt 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 2― 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 ž 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 ž 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