Im getting very very frusturated with this setup but yet I am determined to get it running right...

Well currently the car runs but smells rich and after running for a bit it will not restart because the rear plugs foul up pretty bad... The front rotor's plugs look the proper tanish color so I have left the a/f mixture alone.

Robert suggested maybe that this problem is because the tranny mount is worn creating the engine to be at a weird angle making fuel pool into the rear rotor and he suggested maybe lowering my float level. Well I lowered my float level substaintially with no better results then before...

My biggest concern at this point is that this problem could partially be due to the messed up jet hole from the previous owner (its the rear a/f jet that is buggered up... we cleaned the hole up a bit and cleaned up the jet as much as possible)

When I tried to lean out the mixture on the rear rotor (turned the screw out 2 full turns) the car would not even start. The engine would turn over and just die...


I am seriously frusturated with this setup and have had nothing but problems with it for the last 5 months...

My current jetting is:
Idle jet: f9-60
Emulsion tubes: f-16
Main: 170
Air correction: 155

When you drive the car you can tell it is not running right, the power seems lacking for the modifications done and the engine bogs down with too much fuel. Sometimes after letting it idle if you try to rev the engine up you can tell it is only running off of the front rotor. But if you let the car idle and you hold open the valve that lets more air in, the engine smooths out a ton... Its very very offious that the car need more air...

Any suggestions are VERY VERY appreciated, I have never been this angry about anything in my whole life...

Thanks guys (sorry if I bump this a few times I REALLY need help with this)

Oh yes and pictures will be up in a couple hours, ill get some pictures of my float levels, my a/f mixture screw positions, and what the plugs look like after running a while...

 

Pictures pictures pictures...

Picture 1 shows the bottom float level

Picture 2 shows the FPR, gauge and how the line is hooked up you can also kinda see how far in the a/f adjusts are...

Picture 3 is another view of the lower float level

picture 4 is the closed float position

Picture 5 is showing how the one a/f jet is kinda messed up on the bottom...

 

Picture 6 shows what the entire setup looks like so far...

picture 7 is of the carb/filter

Picture 8 shows a closer view of the a/f mixture screws...

Picture 9 shows what the rear rotor plugs (leading and trailing) looked like after about 10 minutes of operation...

Picture 10 shows what the front rotor plugs looked like after 10 minutes of operation

 

have you confirmed that the plug wires to number 2 are adequately functioning?

 

well they are getting spark, the wires are like new, the coils are new, with a timing light it shows that they are getting spark. After the plugs get all black like that I have cleaned them up using a wirebrush and some sand paper making sure to blow off any debris afterwards. I assume the spark is plenty healthy the timing was also reset to the stock position (9 o'clock key position on front of engine) but may be slightly off? It seems to run smooth but bogs hard at high rpms..

and the fuel pressure is set at just under 3 psi...

 

well then how healthy is the engine? any chance that the compression on the rear is headed south?

 

the engine was rebuilt 30, 000-40,000 km's ago. With the plugs out the compression sounds very strong but at the same time I do not have a proper rotary compression tester in my garage...

 

for what it's worth, i think it may be better to listen to the exhaust with the plugs in.

was the rebuild with NEW seals or used ones?

 

There was new apex seals in this engine (I know this from when I was looking in the engine with a mirror, the apex seals have tons of meat left to them) for sure but I am unable to confirm any of the other internals used. The local RX-7 guru I bought it off from said that one of his racer friends built it so he was not sure what it consisted of either but he sold it to me telling me that it was running great when pulled from a wreck...

The exhaust sound sounds normal to me, but like I said after the car idles for a certain period of time its as if fuel floods the rear rotor (this is usually only when the plugs are black and fouled) and you can tell its not firing on the rear rotor and this point and revving it up a few times cures this... But I am still not sure as to what else could be causing this...

 

sorry ...

i wasn't clear with what i meant. i meant when you're listening to compression while turning the engine. it's better to do it with the plugs in, and just listen to the exhaust (with downpipe or manifold removed - watch for fuel leakage if you opt for the latter). that, as opposed to listening with the plugs out.

how OLD are the plugs? maybe you could opt for a hotter plug or maybe a different type altogether. i use the B_EV plugs in my car and they seem to resist fouling with my Dell'Orto much better than the stock plugs. they are also less expensive, so you can experiment between 7 (expensive), 8 and 9 (much, much less expensive) heat ranges.

i don't know. i'm still inclined to think you should check if the spark is getting all the way through to the plugs. it may be leaking somewhere between the cap and the engine. the wire could be broken inside the insulator. it happened with my MR2 before.

if not, then maybe you should experiment with plugs ...

 

I am running the setup below on a 45DCOE for a 12A Street Port....working fine for my engine

Idle Jet = 60F9
Main Jet = 185
Air Corrector = 190
Emulsion Tube = F11
Needle & Seat = 250
Pump Jet = 60
Chokes = 40
Auxilliary Chokes = 4.5
Fuel Pressure = 4.0 psi
Idle RPM = 1000 + - 100
Timing = 8-10 degrees advance
Vacum Advance = Disconnected

No return fuel line...... Front rotor 3 turns out from the fully closed position, rear rotor 2 turns out from the fully closed position. Some carburetors the idle mix screws turns will be different... so you will have to figure out how many turns per rotor does it take for your engine to do the trick...If your rear rotor is flooding or too rich maybe the idle mixture is open to much.... try leaning the idle mixture by turnng it clock wise to close it 1/4 turn at the time and driving it to see how it performs...

 

actually, that's a point that i should have made, too. my Dell has to be tuned differently between 1 and 2. it may be just as simple as that.

 

yes thats the thing... If you look in my pictures I show how my one jet is screwed up. Like I said earlier I tried to lean the mixture out a bunch with the car off and the car would not even start back up??? Whats up with that I tried to start it about 5 times with no luck like that I turned the thing back to where it was and it fired right up...

The plugs (BR8EQ-14's) that are in it right now are about 3 weeks out and have maybe 40 km's on them... I have had to clean them several times though because of the flooding issues...

Maybe I should start by running a larger air corrector jet? Like I said when I turn the valve to let more air in on the carb it seems to run much better...

and isn't turning the jet clockwise richening the mixture because it is blocking off more air from getting in??? Maybe all my problems are caused by the jet whole beening drilled out a small amount because of the wrecked jet that damaged the hole before (I wish I could take a picture of what I mean but its to dark down there...)

I have already tried messing with the a/f screws a bunch but I have not been very successful...

 

A large air corrector jet will make it LEAN on top end. If you modify the fuel inlet (ie, remove the stock filter/funnel looking thing and enlarging the holes) will allow you to even run 3 PSI and it will run fine. How does it run @ idle - 1500 RPM.

 

below 1500 rpms the car runs strong, it just does not even want to hold a steady idle but I haven't really even began to mess with that for the time being.

So I should remove that filter?

When I turned that air valve it seemed like when the throttle was hit the car was more responsive and had more power even at low rpms... I don't know whether or not a larger air corrector would help with this...

 

Removing the inlet filter and others mods will allow the fuel to fill up faster and will prevent fuel starvation/flooding.

try this, let the engine idle and remove the spark plug wires say L2 & T2. If you notice changes in idle, then the engine is good. If no changes, you have low compression.

 

Ok i'll give that a try later tonight when I get home from work. I can almost gaurentee though that there will be a substaintal change because the motor runs very well and has a good amount of power, moreso then I would expect if it was running off only one rotor.

 

Heres the facts as I undertsand them:

1. The a/f jet looks buggered.
2. The hole it was in is probably messed up.
3. The car is rich on idle due to the fact that it fouls the plugs after its idled awhile.
4. The idle a/f mixture affects how the car runs up into the 2-3000 RPM range.
5. Based on empircal evidence it doesn't sound like a plug wire or compression issue.

So first I would verfiy the plugs/coils just by switching the wires/coil for t1/l1 to run t2/l2. If the t1/l1 plugs still come out good then you pretty much know its not the colis or wires. Could there be an issue at the dist? Maybe but you can do the same sort of swap around to make sure its not an igniter or rotor or cap issue.

After you convinced its not an ignition issue, move on to compression. You can check compression using a regular compression checker for 4cyl engines and just hold in the button so you can see the needle bounce for each face of the rotor. You should see it bounce up to around 60 psi or so. This isn't real exact but it doesn't matter because you have the front rotor to baseline from. Do the test on the front rotor first then see if the back rotor gives the same results. If it does then the compression is probably ok for the back rotor given that we know the front rotor is working well.

So now we are really down to the fule mixture. You can do a similiar swap thing there as well, just swap the bad jet with the good one on the front rotor. If the fouling now occurs on the front rotor then you know that the jet is causing some of the problems. If the back rotor is fine, then you know the hole in the carb is ok and new jet will fix it. If the rear rotor show issues, then maybe you need a new top cover for your weber because the jet hole is fouled up or you need to have someone repair the jet hole on your carb.

I had a bunged up jet on my dellorto where it had gotten the tip bent and it would always be hard to tune it to run exactly right. I didn't know this until I rebuilt it recently. I was able to unbend the tip and its seems to work much better. I think it came from RB with this issue because I had never seperated the carb from the intake when I first got it years ago. So keep plugging at the carb, it really sounds like just a bad idl a/f mixture problem but they are hard to solve until you narrow down the suspects.

Good luck.

 

Ok guys I took it out today and messed around with it. First of all I took the little filter out...
Then the car bogged down and wouldn't start so I a little confused so i pulled the plugs and sure enough cover in gas... Did this over again and this time had gas pouring out of the filter.

So I readjusted the float level and moved my fuel pressure to 2.75 psi (on my crappy gauge) and the car seemed to run pretty good but still didn't have tons of juice in the 5500+ rpm range. I am going to check the plugs in a couple minutes and I will report back on whether the rear rotor turned out black or not...

OK, I also tried the removing the plugs on the rear rotor trick and I did notice a massive difference. Offiously this means I have compression in my rear rotor which is great...

As far as the other idea of switching the t1/l1 to t2/l2 plugs I am hesitant to do this because if I did that then the plugs would fire at the wrong time... Maybe I misunderstood you, did you mean completely removed and reconnect the plugs at the distributor? Because where the leading front plug fires will not be the same spot as the rear leading, the worst thing that I could do would be blow back a apex seal at this point...

I'm kinda happy right now that its actually running decent but I guess the plugs will tell all ill get back to you guys on the results...

 

well I checked the rear plugs again and sure engouh the leading plug on the rear rotor is still really black... I am trying to order a new jet to mess around with it see if that helps but I guess I am really running out of options...

 

Did you try trading the a/f jets to see if fouling moves to the front rotor ? Thats seems like the an easy test that will verify that you just need a new jet. Of course if you already have the jet coming in, it may cure it :-)

On the swapping of the ignition components from front to rear rotor, I should have explained in more detail. First I would just swap the wires from the dist cap to the plugs. Just move the leading wire to be the trailing wire and vis a versa for the trailing. Make sure its not a bad wire. Next put the wires back, remember to keep the variables down to one or you won't know what caued the problem. Ok, now do a similiar swap with the coil wires to the dist cap. Then switch it them back if it looks ok. Now swap the coils themselves. Easiest way i can think of would be to physically swap coils in the mounts, makes it less error prone to a mis wiring. Agin put it back if everything looks the same. The only thing left is the igniters. Theres a thread on here about testing those to make sure they are both good. If you have ignition zombies this should narrow it down to one of the components.

Good luck.