Well here I am again with another dilimma lol, so I have a 73 f250 highboy. It has a 390 that I put in it in about april, the inside was clean and the guy I got it from said it was totally rebuilt. Had nothing but problems at first but that was fixed when i put everything new/ rebuilt on it. Everythings new on the motor; distrubuter, fuel pump, carb.. It is my daily driver, I drive it pretty hard but carefully maintain it, change the oil ontime, check the coolant, etc. It never smoked before and just sounds and runs smooth as it gets. Its been stumbling really bad lately, looked in the carb and the fuel bowl looked kinda low so I adjusted the float and it helped it a lot. Heres the problem now: Usually it starts right up i just barely bump the key and it catches, now it takes forever to start, i have to pump it a lot, and it blows a bunch of white smoke when it starts and it blowes white smoke at an idle. And when I take off sometimes it stumbles real bad, it sounds bad/rough and like its not hitting on all the cylinders. Sorry to be wordy but hopefully it is clear, im trying to get this frigured out. I'm thinking I'm going to rebuild the carb tomorrow because thers sediment in it because my tanks are old, I just know smoke is bad and i dont want long term damage on my motor

 

Sounds like your on the right track. Rebuild the carb, and set to factory specs. Install the bugger and tune from there.

 

White smoke is an indication of water in the combustion chamber. Especially when it's a lot of smoke. If it's moderate and especially when colder temperature are a factor and last for a few minutes as the truck comes up to running temps then chances are your fine. And it's just condensation burning off from the temp changes in the engine and exhaust. If you believe the smoke is abnormal when did it start. It could be anything from water in the gas to bad head gaskets. Is it or has it been overheating? Is your coolant level low? I personally start by ruling these possibilities out first. Cause water in the gas can and will cause the truck to stumble and stall as well.

 

What temperature is it when you're driving it?

 

Its not a lot a lot, but I notice it and I know its not right. And yes it does it a little every morning because of condensate, but not like this and now it doesnt go away when the motors warm. And it is winter here in NM so it pretty much always runs at about 120 even though i have a 180 thermostat. I know its abnormal and it hasnt been running good the past few days and I nothiced the smoke today, not to say it just started today. And I havent ever overheated it. Thanks a lot for your replys/advice

 

Also I pulled the plugs on the drivers side and they smelled like gas and all the threads were wet with gas.

 

As stated above, you are on the right track. Rebuild or replace that carb.

 

Ok hope your right.. Ill let you know what happens tomorrow

 

Burning excess gas or running rich as it's knowing will cause black smoke not white smoke. Also have you checked your oil lately for signs of water in there. If there is water in the oil you'll see a milky discoloration in the oil. Also burning oil will cause blue smoke out of the pipe. That's why I'm thinking you're burning water from somewhere it shouldn't be.

 

I agree that you are going to need to rebuild the carb. Don't get me wrong on that fact. Especially since it's flooding itself when parked. That usually indicates stick floats. But doesn't explain the white smoke. That's what I was trying to help you address.

 

I agree but it's not always black. Depends on how rich you are a lighter gray can look white in the sun. I'm thinking idle jets are too far out etc.

 

Ok you have a point that I didn't take into consideration. But It's been my experience that when the unburnt fuel is walk up the threads of the spark plugs that it's gonna be black smoke he see's. This sounds like a case where the more heads the better.

 

Another possibility could be the intake manifold gasket leaking coolant. You can pull the dipstick but unless it's a lot, you won't see it because any coolant will be at the very bottom of the oil pan. If you pull the drain plug coolant will come out first followed by oil. A manifold gasket leak could also be causing a vacuumn leak which could explain the stumble.

 

What did you figure out with your smoking problem?

 

Hey everyone, thanks a lot for all the help and sorry its taken me like 2 months to write back lol. I think the problem was half bad fuel and half something wrong with the carb. I rebuilt the carb switched fuel tanks and drove it that night and It ran great, no stumbling etc. I switched to the other tank on the way home and it started to stumble and not run as good. I'm quite certain it was smoking but if it was water in the fuel it would just be condonsate so whatever.
Aside from that about 3 days later my alternator went out and I hooked up the new one wrong and it burned my voltage regulator part of my wiring harness and cilinoide. Fixed all that and had it going for about a week then my pasenger side wheel bearing went out lol. But its running good now.. get everything new to do with the alternator, new bearings and rebuilt carb lol.
Thanks again