Here's the story. My oil cooler had a crack in it, so i had to take it off and get it welded. For 3 days, my car sat sideways behind the garage on a incline. (the driver's side sitting higher than the passenger's). The cooler was reinstalled last night and now the car run's like total crap. Struggles to idle, backfire's waaay more than usual, and has a slight pulse when i maintain a steady rpm. Also, it seems to be leaning out in a steady acceleration at crusing speed.
I'm thinking something in the primaries got stuck from sitting in the strange position that it did for so long. The problem is less noticeable when the secondaries kick in.
Does anyone have an idea what to look for? I havn't had a chance to get into it and check everything out yet because i had to drive the car to work today.

The car: '79 12a w/ nikki & RB header.
Carb is basically stock. (mech secondaries, and no anit-afterburner valve) I'm pretty sure it was rebuilt by the previous owner not too long ago.

Thanks in advance.

Shawn

 

Change the fuel filter?

 

good idea.




late

 

common guys. im not a noob here. its not the fuel filter. It still has plenty of power up top when the secondaries open up.

 

I dunno, Shawn. I was just in my workshop tilting a clean carb to try to understand the position it sat it, and I can't seem to find what would cause such a thing. Frequently there is an accumulation of sediment on the bottoms of the floatbowls. I suppose if there was enough crap in there, it could've gotten sucked into the primary main jets, and clogged your emulsion tubes.

Here's what I suggest-
Take the airhorn off, and remove the jets on top of the primary booster venturi housings. See if the holes in the tubes are plugged with crap.
You can also remove the next set of jets between them and the side of the carb. They are long emulsion tubes as well, and could be suffering from the same problem. The jets right on the edge are short stubbies, so don't bother removing them. You just chance losing one in grass or gravel.

For stubborn crap in jets, I use pieces of steel guitar string to clean them.
Be careful when installing them, particularly the ones with the delicate heads, as the tops WILL split apart if you tweak them too hard.

If it's spanky clean in there, then I would have to say that you might have a simple ignition problem. Perhaps as simple as a jarred dizzy cap?

Let us know.

 

Remove the fuel jets, too- at least on the primary side of the carb. Use an air gun and blow down into the emulsion tube hole- it won't hurt anything; the delicate stuff is attached to the airhorn anyways.
!!!Watch your eyes!

 

what do you think is causing the excessive backfires? It pops a little when im driving. and most of the time when i turn off the engine. depending on how hot the motor was, it could just be a little cough, or a big flame.

 

Is the dashpot stuck shut?

 

acv..........

 

Sterling: I dont think so, how would i go about checking that?

79+80+84_rx-7: no acv, blocked off. RB exhaust system.

 

The dashpot is the round thing on the back of the carb. It has a white plastic plunger (facing downwards)that slows the throttle closing. It should move in and out with a slight resistance.

 

gotcha. i knew what it was, i just didnt know if there was a special way to check it, or something. hehe

Ill check it out here in about an hour when i go to lunch.

 

Actually there is a procedure to check and adjust, check the shop manual or haynes.