nnamssorxela

As the title states, my 1985 crx HF is running a bit lean (spark plugs are pretty white) on a rebuilt carb. I have the clymer manual but it doesn't seem so have the simple adjustments such as fuel mixture, only how to rebuild (still looking)? It is also hard to start cold which I assume has to do with the automatic choke, or is maybe associated with the lean mixture. Any suggestions? It has fresh fuel and new plugs, but I have not replaced the cap and rotor or wires.

Any suggestions?

-Alex

nnamssorxela

For those that may search for this in future it turns out my timing was way off. the distributor was about the middle of the slot, and I moved it all the way back to advance it to 21* as the plaque on the hood recommends. To do this I purchases an adjustable timing gun, set it to 21* and advanced the distributor until the arm reading "up" on the cam pointed straight up off the deck of the head and lined up with the raised section of the valve cover. Immediately the idle smoothed out and I was able to adjust the idle down to close to the recommended setting.

Hopefully that will improve my fuel economy a decent amount and fix my lean burning issue as well since I was only getting approximately 45mpg.

First time doing this, so if someone sees an error in my ways PLEASE don't hesitate to point it out.

nnamssorxela

I still have a feeling I'm running a bit lean. Is there any way to adjust the mixture or is there something I'm over looking when adjusting the carb?

letank

Vacuum leaks from one of the many hardened hoses, or simply disconnected or loose ends, check around the air filter can, you can always shortened some of them, but it is tricky to remove as you are almost sure of breaking the ends of those plastic tips, so focus on the metal terminals.
The carb bowl vent has been mentioned by some.

nnamssorxela

So there is no mixture/air screw I am over looking? Coming from small engines and dirt bikes is seems like every carb should be fitted with something of the sort.

Should the spark plugs be golden brown? Or is the motor designed to run a bit lean, and therefore have white plugs?

Sera_

The Haynes manual says that on North American models the adjustment of the idle mixture can only be carried out using a propane enrichment kit. Due to this requirement and the risk of violating current emission control regulations, if the manufacturer's procedure is not adhered to, mixture adjustment should be undertaken by a suitably equipped dealer. I can't find any pics of the North American model's mixture screw specifically, but there's some of the UK models.

nnamssorxela

Found this picture, and apparently thats the one. Does anyone know if turning it counter clockwise richens it?

letank

This is a gas screw, so it need to be turned counter clockwise to increase the amount of gas being delivered.

Technically it only works for idle, hence the propane method, but I have the same issues on a old vehicle and it works, start with a 1/4 turn, the idle should increase. I solved my lean burn by 1/2turn.

Tell us how to access it, I was trying to do it, but I cannot even see the plate that holds the idle controller.

Not to bore you, my lean civic has golden brown spark plugs, and it runs lean according to the smog test. I realized a few days ago that the muffler is starting to crack, I can smell exhaust, so a lack of backpressure may prevent to air valve to work properly by diluting the exhaust to properly convert the NOx.

nnamssorxela

Not a bore at all. I appreciate the input. I will check the vac lines and then pull the plugs to take a looksy, maybe the timing adjust sorted things out and running warm is a cooling issue. The timing did sort the hard/stalling/stumbling starts but it's still not perfect. I need to pull the trans, so I will take a look at the exhaust then, but I'm sure it has some unintentional additional venting under there.

EDIT: ALSO, there is a large rubber fuel looking line that comes off a "branch" of the cast intake manifold (starts at the 2 cyl over from the distributor and runs to the manifold base under the carb). It is plugged up with a bolt and I cannot see where it might attach.

crxguy406

Hey nnams, where did you find that picture? (Man, I would REALLY like to get my hands on a copy of whatever book that is.)

nnamssorxela

From an autozone site believe it or not. Not sure where the actual book came from though. But I do know I would kill for one.

http://www.autozone.com/autozone/rep...00c15280061690

letank

Running warm is not a joke, my temp gauge is barely at the middle when the fan kicks in, so make sure that you are not boiling over.

1) make sure that you have the right mixture, 50/50, too much coolant will make the gauge go higher. I run 30/70 because we barely get below 25F. But you need to buy one of those $8 density bulb thingy, and do it with the coolant cold.

2) if you can a hold of an infra red thermometer, it can be useful at $60ish, other get the turkey thermometer and jab it between the fins of the top of the radiator.

Not too sure here, a pict could be useful, the only thing that I can see is the the heater hose to the carb that connect to the rear side of the intake manifold.

nnamssorxela

The hose in question is not the heater hose. The one I'm talking about is much smaller and made of rubber, but larger than the standard vac line. I'll get some pictures when I'm back in town.

Picked up some radiator flush and also some water wetter. I'll take a look at the plugs and see what's up. Then do the rad flush/coolant.