1948 A Running Rough

Chesterton angelo · Jul 28, 2016

Been trying to get it running right. Took
out the carb, cleaned it soaked and used 6
in drill bits #40 and # 53 to clean out the
passages. At idle, the idle screw is
working and I can adjust it. It is just
running incredibly rough. It is puffing a
lot of smoke out the exhaust and burning gas
like crazy. Also when I turn off the gas and
let the motor run dry, right before it dies
there is a 15-20 second time where it starts
idling perfect and stops puffing smoke and
then the motor dies. Anyone have any ideas
what is going on? Could the float level be
causing this? It is not adjusted right and
letting to much gas in? Causing it to run
really rich?

David from Kansas · Jul 28, 2016

Sure that there could be other problems causing your tractor to run rough, but think you may be on the right track concerning the float. If it is getting too much gas, when you shut it off it gets to a point where it is at about the right level, and then of course, it runs out of gas and dies as you stated. Had one get a hole in the float once and I couldn't keep it from flooding. Finally, with the fuel shut off I got it started but had to crack the fuel shutoff open a hair to keep it running when the bowl finally got empty.

Gene Davis (Ga.) · Jul 28, 2016

Sounds like the float level may be too high.

Pappy · Jul 28, 2016

Just got through solving the same problem with my '52 "A". The float was full of gas and would not float. The crack was hard to see, but I found it and then drilled a small hole in the float to drain out the gas. Cleaned the cracked area and then soldered it. Then solder the drilled hole. Tested it in a bucket of gas for a week and no leak. Will install it when I can get to the farm.

NateJD · Jul 28, 2016

Check the float for sure, but if it's good, make sure the bowl vent is clear. I had an A do the same thing. IT would flood out badly and die, but as soon as you turned off the gas it ran fine. The vent gets packed with rust and soaking won't get it out. Need to drive out bowl vent baffles. You can get new ones from carb shops.

Nate

RandyB(MI) · Jul 28, 2016

Since I find it hard to believe that if you even own the drills, you also probably know enough to set float level correctly. I agree with Nate (below) pull out those bowl vent baffles (2). If plugged, it will let fuel run right out the ends of the carb...even when engine is off. Crack it loose at air intake end or manifold end or both and with engine off, turn on fuel and watch it flow out the ends.The fuel level can't rise against the air pressure in bowl from plugged vent so it takes the easiest path to less pressure which is the idle/load needle orifices which will lead it out to carb throat. Yes, it will flow uphill if pressure resistance is less. You can check float by submersing it in glass of HOT water and watch for bubbles from air expanding.

Chesterton angelo · Jul 28, 2016

The float needs to be level with body of the carburetor correct? I checked the float with room temp water not hot and it floated just fine. No bubbles or anything. Just curious Why hot water? Also I have a John Deere H with a DLTX carb and it runs like a top. Can I out that carb on the A and see how it runs? I could rule out the possibility of anything else besides the carb. Would that work?

BushogPapa · Jul 28, 2016

JUST to be SURE, take the cup off the Bottom of the Air-Cleaner and see if this goes away...

Seriously..!!

Mud Dauber nests can and WILL drop from inside the air inlet tube and block the in-coming air to the engine..causing oil to be sucked up and it runs BAD AND Smokes....

FWIW...

Ron.

BushogPapa · Jul 28, 2016

IF that turns out to be the problem, run a piece of garden hose ( with no end on it) up thru where the oil cup would normally be and FLUSH that tube until the water runs CLEAN...!!!!!!!!!!!!

buckeye al · Jul 28, 2016

The beginning to run right just before it runs outta gas is surely an indicator something is choking it!

FIRST THING.... Disconnect the fresh air elbow from the front of the carb & slide it off to the side. Does it behave OK with this elbow disconnected? If yes, the problem is NOT your carb but some fresh air obstruction. Maybe the liner of the rubber hose between the air cleaner & the elbow in front of the carb? Dirt from wasps as suggested by others.

If it still runs badly with this off to the side, then the problem is in the carb. Are you sure the choke spring & wind up is correct? Maybe it's choking all the time because something is out of place under the sheet metal cap on the choke lever assembly?

RandyB(MI) · Jul 28, 2016

Yes...level but 5/8" below bowl lip. Yes you can run the "H" carb on the "A". Fuel/air mixture is what makes them run right...not the amount of fuel/air mixture. I would also use a steel inlet needle/seat from Marks Carb (abt. 10 bucks and free shipping.

Chesterton angelo · Jul 28, 2016

Ok thanks guys.The choke is not stuck. The choke moves freely and it works to help start the tractor as it wont start without it on when it is not warmed up. I will have to try and take the boot off where the air cleaner is attached and see if that works. And I will let you guys know!!! I will also check the float level as well and the bowl baffle vent. I appreciate all the input and advice!!

Bob Collins · Jul 29, 2016

Had a similar symptom a number of years ago with a "B", finally found I had neglected to put one of the brass plugs back in the carburetor...Green tractor, red face.

Mike M · Jul 29, 2016

Like the others say. Check float for leaks and adjust. I set the late ones to 1/2" when inverted from the bowl edge like the early ones. 3/8" just seems to make them run rich on rough ground. Check for plugged bowl vents. Run without air cleaner hooked up to eliminate that as a restriction. And one more thing besides a leaking needle and seat is they can also leak where they screw into the bowl casting where the gasket sits. Many times this surface gets pitted and many of the needle and seats do not have the chamfer on the corners of the hex so the seat gets tight before the gasket seals.

1948 A Running Rough

Chesterton angelo

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David from Kansas

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Gene Davis (Ga.)

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Pappy

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NateJD

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RandyB(MI)

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Chesterton angelo

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BushogPapa

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BushogPapa

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buckeye al

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RandyB(MI)

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Chesterton angelo

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Bob Collins

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Mike M

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