farmall bn won't start.

Anonymous-0

Well-known Member
I have owned this BN since 1966. It has given me very few problems over the years, until two years ago. It had been running fine, but one morning it wouldn't start. I finally have time to try to get it running again. It has an electric start. so I charged the battery and it will turn over. I pulled a spark plug wire and put a spare plug on it and grounded it to the frame. When I ran the starter, the plug sparked a nice blue spark. There is gas to the carburetor, in fact after trying to start it for a few minutes, it dripped gas on the ground. The carburetor is hard to id. I can see schebel? on the mounting flange. I checked both needles they are clean. I set both at 1-1/4th turn out. Thats where I'm at. Any suggestions?
 
It dripped gas on the ground because you gave it too much choke. If you have never worked on the carb, it is due disassembly and a good cleaning with real carb cleaner, followed by a complete CaseIH carb kit. The Marvel Schebel(sp?) is in the parts manual, also in the parts section of of CaseIH.com. If you have good spark, I am assuming you have not messed with the timing recently.
 
To confirm that this is a fuel issue I would take out a plug or two and see if they have gas on them. If they do not I would shoot a little shot of gas down each cylinder and see if she fires and if so this confirms that you have a fuel issue. If it proves to be fuel problem open the line going into the carb and make sure you do not have a plugged sediment trap. If you have fuel to the carb it is likely junk in the carb and a quick dissembly and cleaning would likely fix it. I hope this helps.
 
1)remove air intake from carb.. while someone cranks the engine, hold your hand over the carb and feel for suction. if no suction, check muffler, etc for mouse nest.

2)give the carb a sniff of ether to see if it will hit or not.

i have had one instance when engine would not hit on ether until, i believe, i drained gas tank and put in fresh gas. ??????? go figure
 
Does it still have the factory mag and have you changed points as you mite have got the rotor out of time. Remove all plugs then clamp a plug to the steering rod and hook #1 wire up. Now with your thumb over the #1 hole run the starter then you can see the plug fire when its on compression as the engine turns over that way you know its firing on compression.
 
Also, take a minute and make sure the air cleaner is not plugge. How are the wires? Are they tight on the plugs? are they copper core? If not, replace them. Composite core wires are NOT good for mag ignitions, and not the best for battery ignitions. Also, the core does degenerate over time and the resistance increases. There are other things that could be wrong, but if you have changed nothing and it just won't start, that is where I would begin.

Keep us informed and we will assist in getting it running.
 
Hold you hand over the throat of the carburetor while a helper makes an attempt to start the engine. See if there's good suction on your hand
if there's poor suction that indicates low intake manifold vacuum. Could have a vacuum leak between the intake manifold and engine block. I would also do a compression check and write down the readings. Hal
 
Thanks for all the suggestions. I won't get back at the tractor until the weekend. I will post results then.
 
Checked the compression/spark - timing seems to be right. Removed the carburetor. It was so full of grime and varnish I soaked it in gas for 2 days. Next, I used carb and choke cleaner on it. It"s orange, must be off an old allis. It is a TSX 422. Went to parts store, and got a rebuild kit. Changed out all parts that were in the kit. The gasket that goes between the halves was so brittle, that it broke in two spots. I used it anyway. Gas tank will be a big job also. I hope to do something with it tomorrow. Any other suggestions?
 

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