luvmy73

I reinstalled my old intake after cleaning it, and installed a new quadrajet replacement. When I fired the engine up I let it run for a few seconds and everything seemed great. When I shut it off I see this haze of white smoke coming out of the secondaries... any idea as to why this is happening?

I replaced the thermostat as well, any way to check to see if the damn thing is letting fluid into the engine.

A C

I am not super familiar with Rochesters, but does it smell like gas when it does this? My old Holley would leak fuel out of the rear bowl when I had some crap stuck in the needle and seat, and you could see vaporized fuel coming out the top of the carb because the gas would hit the hot manifold and evaporate.

AC

luvmy73

This carb is brand new, never used before. So I hope there isn't any crap stuck in it yet. Even though there is not alot of the smoke, it is thick and leaves the carb slowely. Do you think it could just be that the carb needs to be broken in?

Vetterodder

I agree with AC, probably fuel dripping from the secondaries. There should be no fuel coming from the secondaries (or from the primaries) after shutdown. Unless your timing has been changed (and it doesn't sound like it has been), take the carb back to the rebuilder to have it fixed.

A C

I am not saying for sure that a leaky carb is your problem, but the fact that it only comes out of the secondaries has me leaning that way.

AC

biggjimm

They are exactly right. I lost an engine due to this. I didnt know why the smoke was coming out of the carb. Just thought maybe it was coming from a intake valve that was open? That wasn't the case, All that extra fuel seeped down past the rings and thin out my oil enough that a rod bearing started rattling. Then an experienced mechanic told me what caused it. Take the carb back before something drastic happens to your engine. Good luck

luvmy73

Actually I installed a new distributor and havn't set the timing properly yet... perhaps this could be a problem.

Also, just let me verify that the secondaries are the flaps on the top of my quadrajet. The smaller of the two sets.... right? When I look down into them I can see these funnel shaped things.

duntovlives

the secondaries are the rear flaps on the carb. they dont open until a vaccuum drop causes the chole pull off to return and the engine "sucks" the secondaries open.

when the car is not running, or running at an idle, the secondaries should be closed.

as to your question about if u can check to see if it is leaking water, the engine should build pressure in the cooling system after the thermostat opens. this will cause the rad hoses to become hard. if u have a very large leak then it will fill a runner (if the valve is closed) or fill a cly if it (the valve) is open w/ coolant.

i would check your timing b4 u get too concerned, if the timing is off it can cause the problem u r describing.

luvmy73

OHHHHHH the smoke was coming out of the primaries then... not the secondaries.

Vetterodder

Based upon no mention of any other problems, I still suspect a carb problem. If there were other problems (poor idle, backfires, etc.) I'd take a close look at timing issues. I hope I don't sound unkind but, unless it's in an emergency situation, I don't understand why someone would not reset the timing if it had been disturbed. Did you experience any run on, i.e., did the engine cough, sputter, or otherwise act like it was still trying to run? If so, retarded timing might be the problem. On a carbureted engine, fuel flow can continue as long as there is a vacuum signal to the carb. In run on, only one or two cylinders may actually fire but still cause the engine to turn over. This can draw fuel from the carb which isn't ignited and give the results that you're experiencing.

luvmy73

First on all you are not being unkind, your advice as well as everyone else is invaluable to a semi-rookie like me. I had to pull the distributor to install the origional cable-driven tach one so I figured I might as well pull the intake and clean it as well. The guy I bought the distrubtor off of said it was in perfect working order. When I reinstalled the new distributor I was a little lost when it came to setting the timing. I followed some instructions provided by Lars and it fired right up. I start the engine again for a couple of minutes each time, and this time no smoke came out. Perhaps I should let it run a little longer, but I don't want to do any damage. Would it be ok to run it for 10 to 15 minutes without doing any damage to see if the smoke reappears? Otherwise I am getting it to a mechanic to have it professionally looked at. I really can't afford ($$) to do any damage to this car.

Once again thank-you all for the great advice.

Mike.

luvmy73

I experienced no run on, or anything of the sort. The engine started up on the first turn of the key. I did expereince, at least what I think, were a few backfires the first time I let it run. (the carb seemed to cough, and then a little puff of air/smoke came out). This only happened twice and has not happened since.

I highly doubt (at least I hope) it is the carb since I purchased it off professional carb restorer. I did my homework and many people said his work was impecable.

Any other thoughts?