Almost....but not quite there on starting

Travis W

New User
HELP!!!!

1949 model A John Deere. This tractor has had a lot of work done to it. We"ve rebuilt the carb, and have checked it about half a dozen times. I got it started, ran it for 10 minutes....ran beautifully. Turned it off to "share the moment" and can"t get it started again. It is getting air, it is getting fuel (we think) appropriately. Magneto is sparking. That"s all there is on it, so I have no idea why she won"t fire again. I wonder if it is possible for the magneto to not spark hot enough? I have NEVER had the magneto off - and like I said, it ran great for a short while.

I"m seriously almost ready to throw in the towel. I followed advice from a previous post (My Poppin" Johnny Won"t Pop)- the carb is not leaking back through to the engine. I thought the air breather might be completely plugged up, so I took all lines off the left-hand side. I tried ether today....I got a "pop" and every now and then a "pop-pop" - but that was it. Worked on it on and off for over 5 hours today. Turns over great.

I adjusted the float on the carb to 1/2" from the top of the bowl as per a manual for Marvel Scheblers that I pulled down. Verified it is functioning appropriately with fuel. Have tried multiple idle and load settings, including those from the book (1 1/2 to 2 turns for idle; 1 turn for load). I had a friend over that works on airplanes for a living.....he"s as stumped as I am. I surrender, oh ye gurus....
 
Those carb settings seem just a little high for a gas tractor. I'm assuming it's gas and not all-fuel. Open the petcocks underneath and see if you have any gas run out. If so, dry the plugs and try it again. It may just be flooded.

I've seen these old poppers run on a pretty small spark, so check that there is any.

Good luck!
 
Well you only need fuel, air, spark and time to make it run. So since it has run, time should be good. Air, should be good since you unhooked everything. That leaves spark and fuel. Check spark at the plug (or try some new plugs - champions aren't so). Also after some cranking pull the plugs and see if they are wet. If they aren't, then I would say you aren't getting fuel. Pull the plug on the bottom of the carb to make sure you have fuel and not just a little tiny bit. You can always try pull starting it, but that shouldn't be necessary. Have you checked to make sure a valve didn't get stuck open and create no suction?

If you still can't get it to run, drop it in a box and send it COD to me. I will be glad to take it off your hands. :)
 
Travis,
You might try setting the timing on the mag if you have a manual. real late settings will cause the problem you are describing.
also the float setting on a DLTX72 carb if that is what is on your tractor is 3/8 inch.
Rich
 
Travis I'm working on a 46 A that is acting pretty much the same way. I've removed the plugs and it seems they are wet. So I'm leaning toward carb problem. Have you done a compression test? I brought a tester home last nite and am going to try that angle. Also I wonder if it is possible for the manifold to have a crack between the intake and exhast when it warms up.Just a tought! I don't know anything about John Deere 2 cylinders so I'm not much help. They sure are a different breed of engine. Just food for thought. Good luck and don't give up Dale
 
Hey Travis,
If it ran and you shut it off it shouldn't be gas or air. My bet is the mag especially since you haven't touched it. All the other stuff while they may not be perfect, it should at least start. No spark, no run. I would start with something easy like giving the points a good quick filing and reset them to 15 thousand. It could have a weak coil but usually once it cools down it should at least start. Good Luck!
John
 
Try taking the float out and checking it for a leak....see if it bubbles while holding it under in a bowl of fuel. Unhook the fuel line from the carb to ensure you have plenty of fuel. It sounds like a basic fuel issue.
 
Im with Mark Poss.Mine wouldnt crank for any thing.I pulled it and it started right up.I let it run for a long time and set the carb and had no problems after that.If it dont start its something else as others have mentioned.
 

I would put in a New set of Autolite #3116 Plugs..

The ones you have may be fouled too bad for it to start at this time..

Have you looked at the Points in the Mag..??

Run a point-file through them but do not change the setting..it ran before so it should again..
The more you change, the more that may keep it from running..!
Make sure the inside of the Mag cover is Clean AND Dry...ANY moisture in it will give you trouble..
Ron..
 
You guys are awesome- I appreciate the outpouring of advice.

My dad and I worked on these together- kind of our hobby. He was recently diagnosed with liver cancer, and I wanted to get this one going before Christmas to surprise him. We went in halves on this one and a '39 hand crank. The hand crank runs good. I'll try locating the autollite plugs and pull starting first. I had an old head working the carb over with me- I am getting good fuel and the mist from the petcocks. The plugs do get wet though, so it might be flooding out (but I don't really get the strong gas smell).

Hope you all have a happy Thanksgiving!
 
Have you tried to pull start it?If it pull starts, put 1/2 turn more on the impulse sping and try again, it worked for me.Mae certain points are clean and set to 15 thousandths.set both carb needles to 1 1/4 turns for clean carb,may need a little more idle for dirty carb.Buy new plugs and gap them to 20 thousandths.open the drain on the fuel bowl and let some run into a cup does it look clean?Close the choke,set the throttle so the stop on the throttle shaft is just off the spring.roll it ver one time and move the choke to 1/2 and roll it again If you have checked/set these items it will start.
 
In the earlier thread, you said:

"What I"m seeing is that the clutch side cylinder has gasoline POURING out of the petcock".

And in that same thread you said:

"...when it first started, the smoke was black. It did not contune smoling. Subsequent attempts showed white smoke- which I thought indicated it was too lean."

And in this thread a few days ago (21 Nov) you said:

"I am getting good fuel and the mist from the petcocks. The plugs do get wet though, so it might be flooding out".

All of those symptoms are typical of flooding, and may indicate you have a leaking needle valve, or that the needle valve seat isn't tight and gas is leaking past the seat gasket.

You've mentioned that you've "..rebuilt the carb, and have checked it about half a dozen times", but have you positively verified that the needle and seat are sealing properly? If they're leaking, this could be the source of your problem. And you can easily check this with a couple of different tests - one that F-I-T mentioned earlier was to loosen your carburetor from the manifold and hold it away with some small spacers such as wire rods or nails. If you have a leaking needle and seat, you will eventually see gasoline leaking out of that space held open by the spacers, and that leaking gasoline will run into your cylinders and will eventually fill up your crankcase. The other test is to use a float level test manometer that you can make yourself out of hardware store parts to verify your float level is correct and stays constant at the 3/4" level. If tractor is not running and the level creeps up something is wrong with your needle and seat or its gasket since gasoline is obviously leaking into the bowl when it shouldn't.
Float Test Kit from the late Pat Brownings website
 
DAN - YOU AND FIT ARE SPOT ON. I DIDN'T GET THE LEAK RIGHT AWAY, BUT SURE ENOUGH, THERE HAS TO BE SOME KIND OF PROBLEM WITH THE NEEDLE OR SEAT. HOW DO I GET THIS STRAIGHTENED OUT? DO I NEED TO MAKE MY OWN GASKET? ADVICE IS SINCERELY APPRECIATED.
 
Well, I'm a poor one to answer your questions because I've never worked on this specific carburetor. But the attached excerpt from the parts book shows a gasket between the needle valve seat and the carburetor bowl (item #34).

If it's anything like other needle valve seat gaskets, I wouldn't recommend trying to make one, but would buy one from one of the usual suppliers, such as Robert's Carburetor Repair. (Theirs lists for $0.57.)

However, before one assumes the gasket is the culprit, check the needle and seat itself to ensure they seal properly - and check to ensure the carburetor bowl is not cracked or has some deficiency that might let fuel pass through from the needle zone into the bowl itself. There can be lots of nasty little gremlins that might be the cause of fuel overflowing the bowl, and only a keen eye and a detective's mindset can find them.

Good luck!
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