Super A engine quitting on me

Sun Dec 01, 2013 10:18 am

1953 SA 12volt alternator conversion by P.O. Carter UT carb.

Tractor has been running o.k. but it will die after 10-15 minutes. Sometimes longer, sometimes shorter. Will start up right away but each time restarted it's runtime is shorter. Acts like ignition switch is being turned off. No stumbling or surging like a fuel problem. It just cuts off.

When it first did this a couple weeks ago I worked with the carburetor/fuel system. Took carb off and cleaned it out. Checked/changed screens in carb and sediment bowl. Nothing jumped out at me as being an issue. Ran fine for awhile after putting it all back together. Shut it off thinking I solved the problem.

Fast forward to yesterday. Put on snow chains and started it up. Ran for a bit and then just quit. No load has been put on it when it dies. Again just like the switch was turned off.

Coil was not hot. Only part I threw at it today was a new condenser. Once I did that it wouldn't even start. I now have a no start condition! Put the old condenser back on and still wouldn't start.

Check for spark now. Pulled lead from the coil out of distributor cap and grounded it. Pulled starter rod. No spark! What it did do is spark when I shut the ignition switch off. Then it would spark again when I pulled the knob back out. I could push/pull the knob and it would spark but then sometimes it wouldn't spark. There was definitely no spark when I cranked the engine over.

Should the secondary lead from the coil to the distributor cap spark like that just turning the ignition switch on and off?

I'm starting to think the 12 volt conversion is now messing with me. Maybe...maybe not? The ammeter is showing a charge. Some other component not happy? Maybe the conversion isn't quite correct and it has burned something out? Ignition switch is failing or has now failed? I've reviewed FarmallBob's wiring diagrams for the 12 volt conversion. I did notice when I looked at the ignition switch connections on the tractor is there are 2 wires going to each post not 1 on one post and 2 on the other post as in the wiring diagram. I also do not see a warning lamp or diode in the system. I have not unwrapped the tape where the splices were made so maybe a diode is buried in there. Would not having the lamp or diode cause problems?

I'll be back at the farm on Monday to do some electrical/ignition system review and can get some pictures of the connections. In the mean time, any thoughts on the issue would be greatly appreciated.


Re: Super A engine quitting on me

Sun Dec 01, 2013 10:41 am

To start with, make sure that when you changed the condenser and back you did not get the bare terminal against the case of the distributor. Use a test light or voltmeter, for the following: Should have voltage at switch side of the coil anytime the switch is turned on. The term of coil going to distributor and the terminal on side of distributor should have voltage when points are open and NO voltage when points close, so you should see a test light flash at that point as the engine cranks over. If no voltage at the distributor remove the lead and see if you have voltage. Yes, check for grounded in distributor, including the insulator where the stud goes through the side. No voltage, bad coil.

Regarding your original problem, have you tried removing the plug in the bottom of the carb to see if you have good gas flow as soon as it dies? If not good flow, check for restriction in flow or dirt in float valve, do not overlook vent in gas cap, that will also cause one to die after a few minutes once it draws a vacuum in tank. A bad coil can also cause that problem, in addition to a bad condenser. When you converted to 12 volts did you replace the 6 volt coil with a 12 volt one, or add a resister?

Re: Super A engine quitting on me

Sun Dec 01, 2013 11:24 am

I'm putting together my test light, multimeter and other assorted stuff to take back to the farm tomorrow. I'll check the items you suggested John, including checking to see if I grounded the condenser. I thought I bent it a bit away from the housing but who knows. I haven't had to go thru all this type of testing in a number of years so I'm a little rusty. Where to test and how to test is greatly appreciated.

I'll definitely go back to the fuel system to double check things.

I did not do the 12 volt conversion. It came that way when I bought the tractor. It came with a 12 volt coil on it. It is a "Standard" brand coil. There is no external resistor so I'm gonna guess the 12 volt coil has an internal one. I was gonna get the part number off it and look it up to verify if is is internal. I do have a new spare 12 volt coil which has an internal resistor. I was gonna put that one on to see if that made a difference.


Re: Super A engine quitting on me

Mon Dec 02, 2013 6:15 pm

Back in business!

Fuel system:
1. New style tall gas cap - one of the two vent holes was mostly blocked. Cleaned it out with a piece of wire and then blew it out with compressed air. Air flow was much better after cleaning it out.
2. Gas tank - small round cork gasket(about the size of a quarter) in bottom of tank. Fished out with a piece of wire. I had seen it in there before but hadn't fished it out.
3. Gas tank - piece of rust about the size of a bb in bottom of tank. Would not come out with a magnet so I fished it out with one of those vintage match holders for lighting pilot lights. It has a plunger on one end and little jaws which open up to hold the match. Only took two tries to grab the rust piece. Tank looks pretty good beyond the one piece of rust I found.

Electrical system:
1. Distributor wiring - replaced short wire from negative side of coil to distributor. Looked a little frayed and suspect.
2. Coil - replaced old 12volt coil with a new 12volt internal resistor coil. If I did the test(s) correctly as John suggested, I felt the old coil was on its way out or had finally failed. Did not get the blinking light when the points open/close. Once I put the new coil on and turned the engine over, the test light flickered with the opening and closing of the points.
3. Condenser - was not grounded after removing and reinstalling so I left the old one in there.

Turned on fuel valve. Fired right up! No start problem solved. What solved that...don't know.

Hopefully the cutting out problem is also solved. We'll see. I ran it for about 15 minutes without a problem.

Thanks for your help John!


P.S. Cork gasket I found on the bottom of the gas tank. Not sure if it was moving over the outlet but I know it shouldn't be in the tank.
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Re: Super A engine quitting on me

Mon Dec 02, 2013 8:58 pm

If the light did not blink with the old coil, but did with the new one, it sounds as if your old coil had failed. That gasket is about the size that was used in the spout of some of the older 1 or 2 gallon metal gas cans. The ones that had the metal cap that screwed on a spout, then the cap had a smaller spout on it.

Re: Super A engine quitting on me

Tue Dec 03, 2013 2:56 pm

I don't think you have an electrical problem but a "lack of compression/suction after warm up" problem. The hints are that it has started repeatedly cold after dying hot indicating a working electrical system and the only change in the engine from running to not-running is its temperature (not fuel flow, carburation, etc). I suggest measuring the cold and hot cylinder compression...if significantly different and low overall, you've found your tractor's problem.