Smoke/Carburetor question

O

old46ford

Senior Member
I am working on getting this old girl back on the road after being in my grandfather's barn since '68.

The engine is original and with 83,000 miles on it. I have no clue what was done to it since 1946, as my grandfather has passed on.

I am trying to get the carburetor tuned right. I can't get her running with the choke open all the way. She will just cut off.

I also have some white/blueish smoke coming out the exhaust when reving the engine. It doesn't it doesn't smoke when idling... and gets less as the engine warms up... but still smokes when reving. I don't believe it's coolant/head gasket related, as the same color smoke comes out the breather tube and it can make smoke rings out the exhaust ... kinda cool.

The motor has been running with MMO in the gas and I believe I've all but burned through that.

Any advice on getting the carb adjusted right and decreasing the smoke, would be helpful. I haven't had it out on the open road yet, and can't really afford a full engine rebuild right now. I am going to test compression later this week.

Thanks...
 
The smoke can be from worn valveguides or rings either stuck or worn that is common and not a big issue will get better or worse when you get to drive it.
The carb probably needs a good cleanup and a gasket set to work right.
Get the carb done and get it roadworthy then drive for a while to evaluate what really needs to be done.
 
Activating the choke leans the fuel/air mix. You may have an internal fuel leak or a stuck float valve. If the mixture adjustment screws are too far out, it could be due to that. If they are all the way in, it has fuel getting in there from somewhere.

I had something up & locked but it wan't my landing gear. See post 11 for correction.
 
Last edited:
Need of choke...2 reasons comes to mind...1 to make the mix richer cause some jets/nossles are clogged up. 2 to raise the idle speed perhaps because of vacuum leaks...is the hose for wipers ok ?
plug it up and check for any difference.
 
Having the choke on actually richens the mixture indicating it's not getting enough fuel. More than likely there are plugged up passageways in the carb and it needs a good cleaning and probably a new accelerator pump.
 
I am with the others... get the carb rebuilt/tuned up and drive it for a while. The rings may just need nudge from sitting around for so long.
 
Usually, a "poorly adjusted" carb will only produce smoke when its mixture is too rich and usually that smoke will be black in color. White/bluish smoke is usually produced by excessive oil in the combustion chamber....
 
I had it bas ackwards. If it runs better with choke then something is likely plugged up and not feeding fuel. Choking the incoming air enrichens the mix. I don't know what I was thinking about this morning but it wasn't about fuel delivery. This would indicate problems with blockage if it runs better with choke actuated. An excessively lean F/A mix will also cause back fire through the intake manifold. Choking it will enrichen it enough to stop that unless it is just not getting enough fuel due to blockage in the system or an air leak in the fuel line prior to the pump causing it to draw some air in or a fuel cap vent that no longer vents.

Now light colored smoke could be steam from coolant seepage. Blue smoke is oil burning. Black smoke is an overly rich mixture.
 
old46ford said:
Can a poorly adjusted carb or carb issues cause the white/bluish smoke?
Click to expand...


No, the problem is oil consumption. I'm sure a compression check or leak down test would indicate that. The carb needs to be gone through after all those years, and use the MMO in the oil and drive a lot. Should improve.

Sal
 
rotorwrench said:
I had it bas ackwards. If it runs better with choke then something is likely plugged up and not feeding fuel. Choking the incoming air enrichens the mix. I don't know what I was thinking about this morning but it wasn't about fuel delivery. This would indicate problems with blockage if it runs better with choke actuated. An excessively lean F/A mix will also cause back fire through the intake manifold. Choking it will enrichen it enough to stop that unless it is just not getting enough fuel due to blockage in the system or an air leak in the fuel line prior to the pump causing it to draw some air in or a fuel cap vent that no longer vents.

Now light colored smoke could be steam from coolant seepage. Blue smoke is oil burning. Black smoke is an overly rich mixture.
Click to expand...

Now you are talkin I didn't want to slap your keyboard so early in the week. I knew you would come to your senses. How old was that distraction you encountered on the weekend "LOL" :D

R
 
On a positive note (I think)... I did the first compression test on this old girl today. Actually, did it twice... I got from 98-100 on all cylinders warmed up, throttle open, etc... I don't think that's bad for a 71 year old motor that I don't believe has been overhauled.

One plug had some sludgy/oil on it. What could be the cause of that?
 
These are fairly good numbers. Oil on a plug means you are getting oil into the cylinder. Source could be around the rings, valve stem, etc.
 
Thanks. I want to get her on the road and run it some... but of course my first stop has to be state inspection... uggh. I think the 100 psi average is good for driving right now. one day she'll come apart... maybe when my boys are a few years older and can help more. Right now, they just want a ride.
 
Not by chance a piece of the intake gasket missing...that will give you lousy idling and suck some oilvapor from the liftergallery into engine.
 
You must log in or register to reply here.
Back
Top