John Deere 50 tractor won't start

A few months ago I purchased a 1954 John Deere model 50 tractor. It is in very nice condition and had no issues the many times I have started it. This week I welded a step for the tractor. I drill holes in the uprights to bolt to the axles. To insure the right position, I welded the cross pieces while bolted on the tractor. Before welding parts connected to the tractor I disconnected the battery. It must have been a bad idea to weld parts bolted because now the tractor won't start. This tractor has the special sediment bowl that automatically shuts off the gas if there is a problem. I suspect this might be what is keeping the tractor from starting. I choked it a lot and gave it some throttle. Enough I should have smelled gas, but I did not.
I have other 2 cylinder tractors but all are older style with gas shutoff on the sediment bowl. can anyone tell me how to do a function check of the automatic sediment bowl?
Does anyone have any other ideas? The battery is charged, the engine turns over fast. Everything seems normal except it won't start!
Thanks, Bob
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Wipe the bottom of the carburetor to see if it has a gas leak. If gas leaks out while sitting they will take a lot of cranking to get them to start . On top of the fuel shut-off there's a" THUMB NUT", loosen it about three turns, then push down and watch the gas in the sediment bowl for gas moving around ,hold this down until it stops . The tractor should start . Assuming that gas is the problem .
 

And Always check the engine Oil, to see if the crankcase is full of Gas (from a failed Diaphragm in the Auto-shut-off..

I would install a Manual shut-off, if it were me..(just for security).., but that will not prevent gas from going down the oil line, into the crankcase, if a diaphragm would fail..

Have you checked compression..??
I have seen some 2-cylinder tractors loos compression over long storage times and need a shot of oil in the cylinders to establish a ring seal..
Ron..
 
Checked the carburetor bowl for leaks. Even took it off and cranked the engine to see if the carb was getting gas. It is. The thumb nut on the sediment bowl. it is so loose it seems to not be screwed into anything. I tried pushing on it and watching the sediment bowl but could not get gas movement.

I cranked the engine for a long time, no start.

is it possible for me to change this out and put on a sediment bowl with a manual shutoff?

Since I know gas is getting to the carburetor, I am convinced it is not a gas problem.

Could the welder have done something to the electrical system?
 
I checked the engine oil, no gas in the oil. Did not check compression but was driving it about 10 days ago. No problems then.
I believe I've ruled out a fuel problem. What could welding a step bolted to the axle have done to the electrical system? Could I have burned up the points, or ruined the coil, etc?

Before I welded the step while it was bolted to the tractor there was no issue?

Thanks,
Bob
 
If your amp meter works when you turn on the switch it should drop just a little. Pull off a plus wire and stick a screw driver in the end and touch it very lightly to the frame or engine block. Turn it over you should see it spark . If not play with the switch a little have seen them bad. It could have a bad condenser also.
 
Pull RH spark plug, hook it to the wire, ground the plug, turn switch on and crank motor with starter-should see a good spark. If no spark, trouble shoot electrical system. If a good spark, it is the gas supply or carb.
 
Fuel or ignition issue most likely. Takes minutes to check both with minimal tools. Suspect fuel problem? Shoot some fuel or carb cleaner in the intake on the carburetor. Crank and see if it fires. If it does you have a fuel issue. Suspect ignition problems? Hook up a spark tester (cheap and handy investment) between a spark plug and ignition wire or pull a plug and ground it. Crank engine and check for spark.
 
Might be just a coincidence , take the condenser out (doesn't need it to start and run) but WILL prevent it from starting and running if it is shorted out. Happened on brothers 520. Same problem you describe. I assume you squirted some fuel in the manifold when you had the carb off and it didn't help? Points may have just finally skinned over also. Center carbon post in dist cap fractures also causing this.
 
An engine needs compression, fuel in the correct ratio and spark at the right time.

You need to trouble shoot........

I also think disconnecting the battery when welding is foolish, leaving it connected provides a sink for any stray current.
 
There is no spark to the plugs. The Ammeter does not move when I turn on the switch. Both terminals have current but nothing going to the distributor from the coil? I hooked a test light to the coil wire going to the distributor and touched it to ground while cranking the engine. Is this the proper way to check the coil? Does this mean the coil is bad? The switch seems to be working, it will turn on the lights. I am at a stopping point since I have no power through the plug type wire from the coil to the distributor. Am thinking of ordering coil, dist. cap, points, condenser, rotor, spark plugs.

I took this tractor to our county fair three weeks ago, disconnected the battery so no one could start it, left sit there for 5 days. Connected the battery, it started right up and I drove it home. Had it started once since then, but since my welding on the step it doesn't run. That's why I believe welding did something to it. I am at a loss!

Thanks! I appreciate your time and reply.
 
I have always disconnected the battery on any vehicle when welding. It is my understanding that if the welding current goes into the battery it might explode? However, I've been wrong before. LOL!
Thanks,
Bob
 
Have you got a running tractor you can pull the coil off and put it on your 50? To be honest that's the only way I have to check the coil. Otherwise, no spark it could be switch,points,condensor,cap rotor, wires,plugs.
 

Well, it should not have caused any problem....but, I suppose it will be good to check the ignition..

Should be easy to trace...if the Points have power...

Ron..
 
I'd make sure the points aren't a little corroded first. The definitive way to test that is to pull off the cap and bump the starter until the points are closed, then turn on the ignition and put a test light or voltmeter to the moveable side of the points. If the light goes on, the points aren't quite closed or are corroded. If the light doesn't go on, use the probe of the test light to pull the points open. If the light comes on, then goes out when you use the probe to let them close, you have a normal situation. After that I'd move to the fuel system. RonMC
 
I have 3 two cylinder John Deere tractors. A 1947 styled B 6volt, a 1953 40T 6volt, and the 1954 model 50 12volt. The 54 model 50 is the one we've been discussing. It is the only one with 12volt and a distributor. the other 2 have mags. I have no problem buying a new coil which is my plan for today. I will let you know the result.
Thanks for your time and knowledge. Bob
 
I'm that way to, my 50 is the only 1 with a coil, All the rest are mags or diesels. I've swiped the coil off my 610 bobcat to check and I have an extra coil laying here if you're close to west central Iowa.
 
Thanks to everyone who responded to my post. All were helpful. I replaced the points, condenser, rotor, dust cover , cap, coil and plugs. I barely hit the starter and it was running like a champ! I can only assume that the welder damaged the coil or condenser. Everything else looked ok. I probably would not have had to replace all these items but who knows when it was done last? Now I don't have to do a tune up for a long time. thanks again everyone, Bob
 

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