We got the car out of the garage with the help of our neighbour.
I planned to run it 30 min like you said, so I fired it up, held it with gas at 1,5-2k RPM.

And after a minute of running my dad noticed very few exhaust flowing from the muffler and much greater amount from the small exhaust pipe.

Big flow on the left from small pipe under the car and minimal flow through the muffler, especially in comparison with the small one.

After 2/3 minutes the engine wouldn't spool up with 50% or 100% of gas pedal, it just held same RPM, and shortly after that it dropped significantly, and died after few a seconds.

We figured it might be clogged exhaust, specifically - thermal reactor as it got SOO much gas and oil after rebuild (many start attempts with chambers full of oil and flooding many many times), and also not being heated up properly for once in the last 20 years.(The car sat for loooong time before I bought it).
And just before dropping all exhaust system, because it's too annoying to start from the thermal reactor. I'll do a fuel pump flow test, as I didn't do it on the new pump, just checked pressure and corrected it with a regulator.

But I'm happy we have some idea where to look next, and not just blame the carb.

 

The thermal reactor is just an empty chamber. It's not like a cat. If something is clogged it's more like the muffler or pre-silencer.

 

Hmmmm okay, we'll inspect everything thoroughly.

 

Today we tackles some things, including:
-exhaust system
-TDC
-ignition
-fuel pump



Here I have diagram of exhaust system. Last time almost all of the exhaust gasses we're coming through the cooling air pipe, and that should only expel clean air if I understand correctly.



Schema for the exhaust system. Insides of a thermal reactor.

After taking the muffler and heat exchanger off, we tried starting the car and no sudden change (it didn't start, but that's probably due to being flooded).
We we're hoping that there would be a clear sign of clog in the heat exchanger, as the thermal reactor is empty like KansasCityREPU you said, but the insides of the heat exchanger are completely clear of any clogs, muffler looks okay too. We also disassembled and cleaned the ACV

I'll borrow a fog machine and look deeper inside them but I don't have high hopes for this being the problem. And below is a schematic drawing of the heat exchanger.


sorry for the crude version, but I forgot to take a photo from the insides of it. (And yellow is just holes)

After that we again measured the TDC, and again it was off from the factory marking.


Not my photo, but our TDC is roughly at the green dot.

To measure the TDC we poke a endoscope through the spark plug holes at the rear rotor, mark when we see a apex seal in first trailing then leading hole, and exactly in middle of those the apex seal should point perfectly horizontally, the rotors are 180° apart from each other meaning the front one is at TDC. Thats our logic.

After that we checked to be sure if the distributor was correctly set, and yep it was good with the factory marking. We don't understand why our TDC is not correct with the factory one, so we stick with the original one.
We installed it to match the factory notch.

Then we deflooded the engine.

After that was the fuel pump test, we got 450ml of fuel in 10s, after some hard math it turns out to 2700 cc/min and the factory spec is anything above 1100 cc/min.
Is it possible that this much flow is restricted by the smaller return side, and with time it overpressures the carb thus flooding the engine?
That is the main question after today.

We connected everything back apart from the muffler and pipe leading into it.

And started the car, yup it started but after a few seconds it slowed down and died with ~500 RPM, that is kind of normal but why does it slow down? Then again, I started it with choke, 3 gas pumps and slightly opened throttle, and it did the same thing dying shortly after this. After that we started it again, held it at 2k RPM but this time it was different, it was running and out of nowhere it died just like that, no slowing down or anything just died at 2k RPM. (My dad has a video of it, I'll upload it tomorrow.)
After that there were no signs of catching or anything it probably flooded again.

But why, why does it lose RPM and dies on it's own?? I can't get it to temp because it dies most times under a minute...

 

The bowls could be emptying and not filling again. You could do a fuel pump volume test. It should be about 1 liter per minute. If that is good, look at the front and rear bowl windows while it's running. Fuel should be 1/2 way up on the sight glass (front and rear). As long as you have good compression, a big vacuum leak or fuel is my new guess.

 

I did volume test yesterday and the outcome is 2,7L of fuel in one minute

 

What is your fuel pressure regulator set at? What kind of regulator is it?

 

It's a holley 12-804, and it is set to something like 2,6 psi, I'll double check it.

 

in my experience the holley requires 6 psi fuel pressure.

 

He's using nikki carb. Don't know how much it's been altered from stock.

 

Regulator has description for up to 10 psi fuel pump and from 1-4 psi output. It's a stock Nikki, I haven't changed anything in it.

 

What fuel pump do you have?

 

It's a MagnetiMarelli, nothing fancy just a fuel pump that matched requirements, it is said to send 1.6 liters/minute and 3 psi of pressure. That's a lie, on it's own it makes 6 psi, with pressure regulator set to 2,6 psi, the flow is up to 2,7 L/min.

 

Here's the video with car dying while just normally running at 2k RPM. It's loud cus muffler is not attached.

 

That sounds like an engine low on compression. I'm guessing the exhaust is off also.

 

It ends on the heat exchanger.

 

that's running on only one rotor.

 

That's unfortunate and would explain the shaking.

 

The first thing to test is the spark at the plugs. This would be the biggest culprit for one rotor not firing or building compression. If that is good, take the thermal reactor of and test each apex seal to ensure the springs under the apex seals a good. Make sure they can be pressed in and not stuck. It would be unlikely they are all three stuck on one rotor.

 

Sorry for the irregular and rare updates but It's my final year at school and I have my priorities elsewhere than only my car .

I had some time with my dad today and we wanted to look closer at the carb, maybe it's delivering more fuel to one rotor than the other.
But before that we wanted to deflood the engine and try to start it, I got the spark plugs out, looked closer and saw this:





Every spark plug is cracked. Every which one.
They are all new, bought last November, and it didn't start more than 20-30 times on them. Nonetheless they had contact with oil and significant amounts of fuel.

I'll replace them and check if it helped.

 

Wow. I've never seen that on all plugs. That will cause some strange issues for sure.

 

Ive never seen plugs Crack, makes me think too lean. Make sure you get the right heat range plugs aswell. Here's some general information. You need fuel, air, compression and spark. Take the plugs out of one rotor turn it over and listen for compression repeat on the other. Make sure you carb is set to baseline based off of its owners manual, if it runs thats a start(dont mess with tuning till the problem is solved). Spark is easy just set the distributor to factor and check for spark by taking the plugs out and visually checking it should be blue (if its not i would check the wires and coils, search how to ohm a coil). Absolutely get a timing light if you dont have one and verify proper timing. If you have a vacuum leak you will have to richen the mixture a lot. In my experience my car had the mixture screws all the way out when it had a leak. For fueling a lean mixture(less fuel) will stumble, won't rev, and backfire throught the carb. Rich (more fuel) will bog on acceleration, backfire through exhaust on deceleration, and have soot on the exhaust. Its also good to check the plugs they should be clean, white and chalky is lean, black is rich. if you dont have fuel pressure and flow it will start losing power at higher rpms. If the psi is too high you will struggle with extreme rich at idle even with the idle screws all the way lean. Once its fixed tune the idle based on the manual, and the loaded circuits. As i mentioned, (lean->no power) (rich->stalls out and bad fuel economy. STAY AWAY FROM LEAN this will quickly destroy a rotary engine, Hope this helps.

 

I'll address what you wrote to maybe closer the problem circle.

I did listen for compression on both rotors and it's consistent.
Carb is set to everything from rebuild kit.
Fuel system is new: soft lines, pump, pressure regulator (because pump gives to much of it), it gives 2,7 liters of fuel per minute at 2,6 PSI.
Ignition system is also all new (aparat from only the distributor), new coil (on leading), wires, rotor and it's cap, igniters and spark plugs they are now BR8EQ14 instead of BR8ET because no one makes the old ones anymore, as I read only difference is 4 prongs instead of 3.
Timing is set to factory and checked with timing light.
I checked before for vacuum leaks. I connected a fog machine to top part of the air box, and there were no leakage found.

Not my photo, but this is where I connected that fog machine

It's also strange for me that all of them failed prematurely.

 

Well we tried new spark plugs.
It fired right up with choke, then I switched it off and the car stayed at somewhat steady 1100RPM no gas no choke just held it, and it was mostly good, but it was running kind of rough.
We started walking around and looking at things just happy it idles and revs quite nice, I tried revving it to 4k (only that cuz new bearings...) and no problem nice response, and man that mechanical fan makes such a great noise for me.
After running for a bit more than 5 minutes the temp gauge started moving slowly up, but after another minute when we wanted to drive out the garage it ever so slowly started slowing down...
Then it gradually descended in RPM, I got into the car and held it with throttle at that same 1.1k but it sounded bad, and I couldn't rev it up, without the throttle it went into the 400' and I caught it there back up to 1k, but eventually it died

It was running rich, looking at the plugs very rich.

That's both leading, but they were all identically black.

At least both rotors have the same amount of fuel, but why does it flood so bad when just running?

-carb was rebuild
-fuel is in the middle of the sight glasses
-richer solenoid is "unplugged" (wire broke)
-the carb I would say is "striped" but it looks like factory and there is no signs anyone messed with it

I'll get deeper into that last one.
-only one vacuum solenoid on the rats nest and one belowe it
-vacuum lines run straight from the carb to the distributor pods
-there's only richer solenoid and no other on the carburetor
-I don't have any more blades in the intake manifold
-oh and yup also one vacuum solenoid on top of the carb (it adds air to the exhaust so it doesn't spit too much flames)
and well that's kinda it

I'll throw some pictures of it below:


No dashpots or whatnot on the left and right of the carb, and in my hand that broken wire for richer solenoid.

Arrows point to only two existing solenoids. (that tape on the alt is for not shorting it again...)

View from th driver side, not the best shot I know, but notice there's no solenoids on this side of the carburetor.

When writing this post I realized there might be a problem with accelerator pump, as there's a bit of fuel around it, it may also somehow allow fuel down the carb.
We'll look into that next.

 

Plugs are fouled because spark is not happening towards the end. You may have an ignitor issue here. Thats my best guess. When ignitors go bad, they do so when they get hot or even warm.