Idle smoke

Trucks lightly smoking at idle, but only one side. The secondary blade has the transfer slot almost square. I can't get the idle screws to change much. They are out 1.25. I took the carb apart and cleaned it. Put in a new power valve. Went leaner one jet size. Made sure the copper wires were still in the idle feed holes. New needle and seat. Rechecked float level. Didn't help.

One time this weekend it started smoking bad. It was idleing for a little about 5 min though. I could rev it and it would clean out, but would still go back to smoking.

Does this sound like a carb. problem?
What else could it be?
Maybe a plug problem?
Why only smoking out of one side?

What color is the smoke? Are you sure it's fuel smoke...and not oil? Sometimes the high vacuum created at idle can pull oil from God knows where...maybe through a bad intake gasket, maybe a PCV tube, or even through a leaking trans modulator. If you're sure it's just fat on one side, carry on. If the smoke is blue, I'd suspect an intake gasket leak.

Smoke looks to be white.

White smoke is oil, black smoke is Fuel. At least I think that's correct, some correct me if I'm wrong.

Before it gets further, I'm not really sure what color the smoke was. I'm thinking it was white. May have been bluish. Don't remember it being real black though.

Something I left out, When it was smoking bad was right after a run. About 20 sec. of wide open. Crap I suppose it could be oil.

Blue smoke usually indicates oil being burned off in the engine. Could be the rings or valve seals, especially at idle. Black smoke can be a carb issue, sometimes from a too rich condition. The white smoke could be steam. Really need to know your primary colors . Just kidding. Hope it works out.

LOL. I hear you talking. I don't know what it is. I'm hoping nothing to major. Motor is fresh and heads too. Maybe 12 runs. Runs good and doesn't smoke, wide open.

Fuel smoke will also burn your eyes while smelling it where oil smoke just smells.

maverick wrote:What color is the smoke? Are you sure it's fuel smoke...and not oil? Sometimes the high vacuum created at idle can pull oil from God knows where...maybe through a bad intake gasket, maybe a PCV tube, or even through a leaking trans modulator. If you're sure it's just fat on one side, carry on. If the smoke is blue, I'd suspect an intake gasket leak.

I saw this happen on a 69 351w that was idling too high and the carburetor had not been adjusted out. Lowered the idle speed and set the mixture screws and it quit smoking but it was an oil smoke and out one side as well.

That gives me something to try. I'll see this evening.

About the idle, I have it set pretty high. Around 1300-1400. Could that cause a problem?

FORDMUD wrote:That gives me something to try. I'll see this evening.

About the idle, I have it set pretty high. Around 1300-1400. Could that cause a problem?

That idle does sound high. Since it is a pretty fresh build you may also want to check for any vacuum leaks and as another member posted make sure you dont have an intake leak anywhere. Last resort pull a couple of the spark plugs on the side of the motor that is smoking and see what they look like.

What's the easiest way to check for an intake leak? Plugs are pretty black. Not really wet though. I thought at first I had a busted power valve, but it was fine. I went from 72/80 to 71/79. Haven't pulled the plugs since then though.

If you've got an intake gasket leak pulling oil into that chamber, its plug ought to be a bit wet with oil and look like butt. I'd pull the 4 on that bank and check them. To know for sure unbutton the intake and if its leaking you'll see it immediately. The port will be all honey brown and wet. Pretty easy fix if it is rather than a tear down for something else deeper. Good luck.

Thanks, I'll check a few things this evening.

Do yo have valve guide seals on the guides?

Bret Powell wrote:Do yo have valve guide seals on the guides?

Boy, there's a good question. I made the assumption. maybe not.

maverick wrote:

Bret Powell wrote:Do yo have valve guide seals on the guides?

Boy, there's a good question. I made the assumption. maybe not.

I did too. I haven't pulled a cover since I put the engine back in. If it will ever stop raining, I may get to check a few things.

Just some info.....

White smoke is Anti-freeze/water or Tranny fluid

Blue smoke is Oil

Black smoke is Fuel