2stroke1971

We bought the car a few weeks back for cheap. It's a 1985 with the 1.1 na motor

When we got it, it was a bear to start, and then when warm would idle down nicely. There was, however, a dead spot off idle which made puling off from a light troublesome, you had to feather and pump the pedal to get past that dead zone. After that, it ran down the road great, the secondaries worked as well. Put about an hour and a half on it like this.

I rebuilt the Nikki, to address that dead spot. While I had the carb off, I was torn about removing the rats nest or not, I wound up replacing all the vacuum hoses, and of course I broke the obligatory delay valves and one of the solenoid valves. I repaired all of them and reinstalled. I used the AC valve to replace the one I broke and capped off the ports that ran to the AC valve. (AC is gone out of there anyway)

There were lots of rotten hoses, some I know must have been leaking.

I re installed the carb, and fired it up. The dead spot was gone. Acceleration was VERY crisp (the accel pump had been rotten!) ....that was a short test drive...

THe next day we drove it for a few miles and when we got back home it idled down and started running poorly. Even giving it gas did not smooth it out.

Tonight, I fired it up again, it started very easily and the choke turned itself off after a while and it was idling nicely although a bit high (1400 or so) I drove it around the block and to a spot in front of my house (I planned to set the idle lower) but then it started it's episode again.

So it seems that a while after it warms up something happens that is making it idle down to 500 and the motor starts shaking. Even holding the pedal down a bit to get some more rpms does not smooth it out, so its not like I could drive it like that even if I did pump the pedal to get going.

I tried the idle speed adjuster but taking it both ways produced NO change when it was running like this. I tried the air mixture screw as well but no help.

It never had this problem before I rebuilt the carb, so something I did to the rats nest or delay valves or carb itself I would think...I may have some lines in the wrong spots...

SO right now, Ive got alot of crap happening:::
1.THe above mentioned thing it does after warming up.
2. The secondaries worked before the carb rebuild/vac lines replacement, but now they do not work. (Linkage is hooked up and I can operate them manually)
3. Looking down the throat of the carb when idling, I see gas dripping out of three of the tubes, both of the primaries, and one of the secondaries...but one of those brass tubes on one of the secondaries is NOT dribbling anything. If I gas it, it does flow a bit.
4. When the car is shut off, gas STILL keeps dripping out of those tubes for a moment! (is that normal)

Plug wires and plugs are new. I am starting to think that I should have ripped out the rat's nest...can something in the emissions system cause my idle down and run bad deal?

If I remove the air pump do I HAVE to remove the cats?

Any ideas or imput would be greatly appreciated!
Neil

2stroke1971

I found a great tutorial about removing the rats nest, I am leaning towards doing that, mostly just to simplify the whole thing. To make sure the secondaries have plenty of vacuum, etc. and to rule out the rats nest as a cause, it is very possible that I boogered something up or hooked something up wrong. No rats nest is better than one that is not working right Im sure.

Really dont feel like removing the cats, I could plug off the air line from the pump, but I wonder if the cats would get plugged right quick w/o any emissions equipment....sort of like if you run a newer car w/o an o2 sensor, you lose the cat quick. It will burn a cherry red, and that will be the end. Dont ask me how I know that.

My son will have his license in a few days, so Im in a panic to get it running well. Im not trying to build a world beater here, or a drag car. Just a neato first car for him that will be somewhat reliable. (truth is Ive fallen in love with it myself and I plan on buying one over the winter sometime.) I am a HUGE 2stroke fanatic, and lots about the wankel reminds me of a 2stroke. Just the lightness of the powertrain and the simplicity, you can feel it. Good times!
Neil

Qingdao

iTrader: (3)

Smokers are the best!

Have you put the car in time at <1k? This car uses a vacuum advancer.

j9fd3s

iTrader: (3)

if you keep the cats keep the emissions solenoids (the relief and switching), really there isn't anything on the emissions rack that could cause a problem.

if you haven't replaced the fuel filter, it should be done (really easy). other than that i'd suspect a failing ignitor, its the ignition module

74RX4

iTrader: (10)

If you install the gasket between the Main body (middle) and the Throttle Body (bottom) of the carb backwards the secondaries will not open properly. The gasket seals a passageway that supplies vacuum to the secondary diaphragm. Wrong way leaves it unsealed. Did you replace the secondary diaphragm?

Gas dripping could be sticking needle valves. Tapping on top of the carb with a screw driver handle sometimes is enough to loosen them. You didn't adjust the floats did you?

Check this hose for your poor idle / running problem. Bottom can split and open when hot, but harden and seal when cold.
https://www.rx7club.com/1st-generati...estion-750125/

Main cat lasted a couple months when I was young and foolish enough to try it. The first two are probably hollow burned out shells already.
You can replace the three cats with a Bonez race pipe from Rotary Performance. Make sure you get the correct year.
Rotary Performance | SA Exhaust

2stroke1971

Thanks all....

I will check out those hoses.
In any case, I messed with it today and got it to where it went into it's phase of idling down, and I had my son keep just enough foot on it to keep it running while I messed with the idle screw. FINALLY, got the idle screw to affect the idle.....got it idling around 1000, then test drove it. I guess it got thoroughly warmed up then, and the idle went up to 1400 when we were done driving it. I turned it back down to 1000 at that point, (I know thats a tad high)....Tomorrow I will see what it does when cold, and where it will settle in at, then I may try to get it down lower.

The secondaries...Im just not sure. I remember hearing them open before I rebuilt the carb...., it would make a nice throaty sound...Im not hearing that sound any more, although the thing will throw me back into the seat when I get on it.....accelaration is much snappier post rebuild......I wll say this, if the secondaries are not working, and I do get them working, it's gonna be a little rocket!
Gawd, I dont know about the gasket ...whether its in right or not, thats gonna bug me.

As for the gas dripping, no I did not adjust the float level, I even dabbed a bit of oil on the needle valve points when assembling....so I suppose thats not normal to have drips steady coming out of the tubes huh? (Last thing I had with a carb was a 340 duster, and I was 17)

At this point, I will not disconnect the rats nest....so long as it seems to be running alright....

I will post some pics tomorrow....and maybe a video. THanks everyone for your help so far!

2stroke1971

After doing some more reading, the dripping down the throat of the carb is NOT normal....worn needle/seat, etc, but mine are brand new. I will tap on the carb later, but its also a sign of high fuel pressure so I will check that. I seem to remember the previous owner saying something about a new fuel pump, yada yada, I wonder if he put one of those universal units on. Also the dripping down the venturi continues for some time after the motor has been shut off, so its like there is extra pressure in the system forcing fuel past the needle and seat and it takes a while to blow down. Got to get a pressure gauge and then maybe a regulator???

Further, I want to replace the check valve.(the return line from carb) I blew carb cleaner through it, but blowing through it by mouth, it did seem to offer a bit of resistance in the direction it was supposed to flow.

Im trying to talk myself out of pulling the carb and checking that gasket about the secondaries. I was looking at some pics, and I dont think I got it in backwards. There was a small brassy jet that peeks through a hole and if its backwards, its covered....I dont think I botched that, but I dont know.

Will the secondaries activate at all if you are not driving, that is, just revving the motor sharply?

74RX4

iTrader: (10)

Secondaries will not activate when the car is standing still.