John Deere B Carb

[gurneejoe]

I am restoring a 39 B. The carb was rebuilt by a carb shop. It runs so rich it fouls the plugs in minutes. It was rebuilt a second time and it is nearly impossible to get it to start. It has a blue spark. When it runs it is smooth and speeds up but it dies after a few minutes now. Not starving. Mag is hot. Fuel is clean. I'm getting tired of messing with it. Is there a rebuilder that actually tests the carb on a running engine before sending back? When I adjust it leaner to reduce the black smoke it backfires and runs horrible.
Joe

 

[Sleufoot]

I’ve had very good luck with Sandhill Carbs in Winger Minnesota. He’s on Facebook and has a website. Tom in Mn

 

[JDIH]

I am restoring a 39 B. The carb was rebuilt by a carb shop. It runs so rich it fouls the plugs in minutes. It was rebuilt a second time and it is nearly impossible to get it to start. It has a blue spark. When it runs it is smooth and speeds up but it dies after a few minutes now. Not starving. Mag is hot. Fuel is clean. I'm getting tired of messing with it. Is there a rebuilder that actually tests the carb on a running engine before sending back? When I adjust it leaner to reduce the black smoke it backfires and runs horrible.
I don't know what carb shop you used but it takes someone with some knowledge of those carbs to do them right. Soaking in cleaner and a new float won't do it. Need to drill out the passages. Also if the throttle plate bushings are worn its nearly impossible to get it tuned correctly

 

[ken44520978]

Sounds like something else may be going on there. Ignition timing or valve timing? Vacuum leak at manifold?

 

[Watthour]

What spark plugs are installed? Heat range can be all over the map with aftermarket replacement plugs.

 

[gurneejoe]

What spark plugs are installed? Heat range can be all over the map with aftermarket replacement plugs.

I have been using Motorcraft 3116

 

[UnstyledB]

I have been using Motorcraft 3116

You might try Champion W89D plugs. This is a cold plug and resists fouling.

Are you sure the fouling isn't from blow-by? Does blue smoke come out the exhaust or crankcase breather?

How about the air cleaner?
Is the cleaner body free of dirt and debris? To eliminate air intake as the source of the problem. try taking the carb inlet elbow off and see if thr engine runs better

 

[gurneejoe]

You might try Champion W89D plugs. This is a cold plug and resists fouling.

Are you sure the fouling isn't from blow-by? Does blue smoke come out the exhaust or crankcase breather?

How about the air cleaner?
Is the cleaner body free of dirt and debris? To eliminate air intake as the source of the problem. try taking the carb inlet elbow off and see if thr engine runs better

You might try Champion W89D plugs. This is a cold plug and resists fouling.

Are you sure the fouling isn't from blow-by? Does blue smoke come out the exhaust or crankcase breather?

How about the air cleaner?
Is the cleaner body free of dirt and debris? To eliminate air intake as the source of the problem. try taking the carb inlet elbow off and see if thr engine runs better

This tractor was just reassembled from cleaning everything. The air cleaner was completely flushed and I haven't put oil in it yet. There is no breather smoke. I will order some champion plugs. I bought another carb from Sand Hill Carbs. It is on the way now. Once I get it I will try and see if it will start better and run without backfiring.

 

[Fixingfarmer]

The adjusting leaner at low idle will cause a backfire that part is normal happens if I shut my fuel valve off as it’s dying down.

Start at 3/4 turn out on the load screw rh side of tractor

Start at 1 1/2 out on the idle screw flywheel side.
I’ve never had to have them farther in than that. Max on a good clean carb should be double those settings 1.5 out on load 2.5 on idle

It’s possible you have some internal seats leaking or a float problem is what I’m guessing where you turn the fuel on and you are fine for a minute but if you let it sit for 15 minutes with the gas on I bet it doesn’t start but that’s where to begin adjustment wise.

 

[gurneejoe]

The adjusting leaner at low idle will cause a backfire that part is normal happens if I shut my fuel valve off as it’s dying down.

Start at 3/4 turn out on the load screw rh side of tractor

Start at 1 1/2 out on the idle screw flywheel side.
I’ve never had to have them farther in than that. Max on a good clean carb should be double those settings 1.5 out on load 2.5 on idle

It’s possible you have some internal seats leaking or a float problem is what I’m guessing where you turn the fuel on and you are fine for a minute but if you let it sit for 15 minutes with the gas on I bet it doesn’t start but that’s where to begin adjustment wise.

Thanks for the info. I'll try that.
Joe

 

[sandhillcarbs]

Joe,
With this Rebuilt DLTX10 Carburetor i rebuilt & Sent you, those problems from before are Eliminated.. I Guarantee all my work! Please post a Video when you get it tuned in & Running the way it should

www.sandhillcarbs.com
218-902-0179

 

[sandhillcarbs]

I’ve had very good luck with Sandhill Carbs in Winger Minnesota. He’s on Facebook and has a website. Tom in Mn

Thank You Tom! See you on Saturday!!

 

[Tom in Mo.]

I would only add that I would put oil in the air cleaner as it does create a small vacuum from the oil bath restriction which changes the dynamics of the inflow of air.

 

[sandhillcarbs]

I Would still like to see that Carburetor. Curious as to the problem that couldn't be found...