Ford 861 Just Quit and Wont Restart - HELP PLEASE

Hi All,

I have a ford 861 with a 12 volt system. Tractor has been running really well and starting easily. However, recently it would just die about 40 minutes into work. Prior to this I have been able to get it restarted but now nothing. As I was trouble shooting, I noted some corrosion on the plug wires so I replaced all plugs, wiring, coil, etc. Still nothing. I have been holding a plug close to the cylinder head and cranking the engine but am not getting any obvious fire. Compression is good and seem to be getting plenty of fuel into carb. any advice would be much appreciated.

You can be more sure of spark by getting a spark tester that goes between the plug wire and the plug. You need to know this before you can go further.

For a problem like this you have to test things and find the cause of the problem before changing parts or you risk adding a second problem. You said you held a plug close to the head, did you mean a plug wire? That's what you should do, pull a plug wire, pull the boot back, and (with a leather glove) hold it near ground while cranking the engine OR leave it connected to the plug and ground the base of the plug and watch for a spark. If no spark, then you know for sure it's an ignition problem.
At that point, start with the easiest, most basic things and work your way up. Take the cap off the distributor and check the condition of the rotor and cap. Pull the dust cover and look at the points (or does it have Electronic Ignition?) Check the point gap. It is possible the condenser is bad but will give no visual indication and is not easy to test. If all this looks OK, then go on to check for proper voltage at the primary side of the coil, constant 12V on the "+" side and pulsing 12v on the other side while the engine is cranking. This is best checked for using a light bulb. Try this and post back. -Will

Hi Will,

thanks for the comments. I should have mentioned I also replaced the condenser, rotor, distributor cap and points, but cant be assured I have the point gap correct. How do I confirm this as I am not able to completely understand the manual on this point? Interestly, I have a 12 volt reading on either side of the coil when the engine is not cranking and it is a brand new coil. I was unable to get spark as you described but I will get a tester for a more definitive result. Thanks again for the recommendations.

Dan- To set the point gap, looking at the distributor with the dust cap and rotor removed, the squarish looking shaft in the middle is the cam and the moveable arm of the points has a plastic follower that rides on that cam as it rotates. To set the gap, you need to keep "bumping" the starter until you have the cam rotated such that the follower is sitting directly on one of the lobes of the cam and the points are open the maximum amount. Then, using a feeler gauge slip it in between the point contacts, loosen the mounting screw and move the points a little so that the feeler gauge feels slightly tight as you pull it out but does not force them open when inserted. What thickness feeler gauge to use? I'm not sure for this application, but I would start with .020" to .025" and I would think it would fire up and run OK in that range, if all else is OK. Before you do the above, first make sure the point contacts align well with each other and if necessary gently bend the moveable arm a little to align them. Some of the junk points they sell today are not very good. I like Blue Streak if you can get them. -Will

Thanks Will. Points set and they are well aligned. I bought a lo-high voltage tester with a light. Light comes on for low voltage, no problem. However, when using on spark plug wire, it did not light when cranking the engine. I then tested on the contact on inside of distributor cap connected to the coil, there was clearly arching but no lighting of the light. This seemed strange to me, but I am no expert here. Where should I go next?

Dan- I'm not sure I understand you - did you check the primary (low voltage) side of the coil with the light as I suggested above? The "-" side (or at least one side) of the coil should be grounded when the points close and be at +12V when the points open so the light should flash when the engine is cranking.
If I understand you right, you say that there is arcing at the center contact of the distributer, right? So, if you pulled the high-voltage wire coming from the coil and held it near this contact while cranking and it sparked as the engine turns (is this what you did?) then it would have to be sparking at the plugs to find a path to ground. Did you check for spark at the plugs since you set the point gap?

Hi Will, sorry for the confusion. Here is what I have done.
1) with the tester, I confirmed that I have power on both sides of coil with the ignition on but not cranking the engine.
2) I pulled a plug wire off a plug and using the tester, I looked for light at the wire while cranking the engine. There was no lighting at all.
3) After I didnt get any light at step 2, I pulled the distributor cap off, and tested the center contact that is connected to the coil (could have just pulled the coil wire and tested). I did this while cranking the engine. While I clear got sparking between my tester and this contact, the light did not go on. I found this strange, as I thought this was high voltage.

I am beginning to wonder if it is a coil problem, but the coil is brand new. So, needless to say, I am stumped that this point. Any additional thoughts would be appreciated.

Dan

Dan- Then I'm not sure about your test light. May be best to go back to looking for sparking. If you pull the end of the high voltage wire coming from the coil off the center post of the distributer and hold it near ground while cranking you should see a spark for each cylinder. If not, then test the primary side of the coil as I have stated above. If you do get correct sparking, then put everything back together (coil wire, cap and rotor) and pull a plug and see if you get sparking at the plugs as described earlier (plug gap correct?) If not, then there is some other problem within the distributer maybe with the rotor or cap. I won't be able to reply any more tonight, maybe someone else here can chime in and help. -Will

Hi Will,

Thanks for all your advice and time, it is much appreciated. I am not sure how much voltage is suppose to go to the plugs but I am getting very little based upon using a volt meter while cranking the engine. Basically, I put the hot wire from the volt meter in the plug cap, grounded the negative wire to the engine and cranked the engine. I got very little voltage. My light also didnt work so all I can presume is that I am getting very little voltage to the plugs. On the other hand, I get plenty and continuous on the positive side of the coil and pulse on the negative when cranking the engine. I have also changed out the coils with no change. Seems like there is a problem in the rotor/distributor or everything is normal and I am expecting to much voltage at the plug. I will continue to work. Thanks again for your time and expertise.

Dan

Dan- You're certainly welcome, I'm just sorry I haven't been able to help you find the problem.
I would say that if the coil primary has continuous 12V on one side and the points pulse the other side to ground while cranking, then the coil should be producing spark voltage (which is thousands of volts so don't try to measure it with a meter unless it is equipped with a high voltage probe setup rated at 20KV !). You should check that by cranking the engine while holding the coil high voltage wire near ground to look for sparking. If there is no spark directly from the coil then either the coil is bad or the condenser may be (don't trust a new condenser - they can be bad out of the box). Also make sure the condenser wire is properly connected to the points.
If the coil itself does provide spark but there is no spark at the plugs then make sure the rotor center connector makes good contact on the button in the inside of the cap (you should be able to "feel" the spring of the connector make contact as you slowly put the cap in place). The rotating contact of the rotor does not directly contact the posts inside the cap which are connected to the plug wires as it swings by in operation, but rather there is a small gap which is designed in to the rotor and cap. Make sure the rotor is installed fully on the shaft and that the small metal clip inside the rotor is in place which holds it in the correct position on the shaft.
Check all these things carefully and post back (maybe start a new thread) and we should be able to help you get it going. -Will

(quoted from post at 15:38:56 08/04/14) Hi Will,

Thanks for all your advice and time, it is much appreciated. I am not sure how much voltage is suppose to go to the plugs but I am getting very little based upon using a volt meter while cranking the engine. Basically, I put the hot wire from the volt meter in the plug cap, grounded the negative wire to the engine and cranked the engine. I got very little voltage. My light also didnt work so all I can presume is that I am getting very little voltage to the plugs. On the other hand, I get plenty and continuous on the positive side of the coil and pulse on the negative when cranking the engine. I have also changed out the coils with no change. Seems like there is a problem in the rotor/distributor or everything is normal and I am expecting to much voltage at the plug. I will continue to work. Thanks again for your time and expertise.

Dan

Click to expand...

Dan, did you get that spark tester yet? It is generally a good idea to properly perform the test upon which all the rest of the process depends.

Hi Showcrop,

Thanks for your question. I purchased a low-high volt tester from Tractor Supply that is for use testing both 12 volt and spark plug wires. I placed the hot end between the boot and plug cap and grounded appropriately. I then cranked the engine and there was no lighting. I peformed a similar function with a volt meter and also had very little voltage at the plug cap. Not sure if I am doing something wrong but was a little surprised as I expected to see significant voltage. As I expected to see considrable voltage, I presumed there was a issue in the distributor so I changed the rotor, cap, points and condensor but that did not change anything. Any advice or education on expectations would be appreciated.

Dan

Hi Dan,
I looked up you Hi/lo tester and the manufacturer says the tool lights and/or buzzes to indicate whether or not voltage is present. While they didn’t make it exactly clear how it operated, could it be possible that it is buzzing but not lighting for your high voltage testing. Just a thought.
Spark Info:
The voltage that makes the spark at the plugs is in the 20,000 volt range and comes as a spike from the collapsing magnetic field of the coil. The spike will be extremely short and not readily readable by a standard meter even one that is equipped with the special high voltage probe. Digital meters can’t lock onto a value and a mechanical meter will be bouncing.
Seeing the spark is a better test for our needs. The color of spark will tell you if it is good enough. A bright blue / white spark that bridges a 1/4”-3/8” is good spark with plenty of voltage to do the job. A yellow / orange spark or lack of spark (won’t jump 1/4” gap) indicates low or lack of high voltage. If you don’t have a spark tester you can get an idea if spark is there just by pulling a plug wire and laying it close to the block. You can use the same trick for the high voltage coil wire as well. Just pull the wire from the distributor center tower and lay it close to the block. Make sure there is no gas spill or other flammable near where the spark is expected to be.

Testing:
Start by testing the low voltage (12v) at the coil and see if it pulses while you crank the engine.
- If the voltage is there at the coil terminals and it pulses on the lead going to the distributor then your points are doing their job.
The points make and break the ground connection to the coil and complete the electrical circuit to the coil primary.
- If you have pulsing voltage at the coil terminals then the coil should be giving you spark from the coil tower to ground on the tractor. That would be shown by removing the high voltage coil wire from the distributor, laying it close to a ground, and cranking the engine.
No spark or weak spark means either the coil or the condenser is bad. The coil boosts the voltage and the condenser gives it the extra kick for the bright blue spark. As stated by Will, I too have seen condensers come bad straight from the box.

- Mark

Hi Mark,

Thanks for the additional clarity, it helped me understand a little better what to expect. I have gone back to the spark method and confirm I have a nice spark at the high voltage wire coming from the coil. After some modification to my method, I also appear to have a nice spark coming from the plug wires. Given this and that I have good compression, I am left to believe i have a fuel problem. I pulled the carb and confirm that there is good fuel flow from the tank and the sediment bowl screen was replaced last year and looks clean. I had a look in the carb and there is nothing obvious but I will order a rebuild kit and go from there. If my thinking is wrong or there are other areas to consider first, I am happy to hear and be educated by the experts.

Dan

Hi Dan,

The only other thing to consider checking electrically before you go to your fuel supply is timing. While you’re there knee deep in electrical you should check the timing to make sure the gear at the bottom of your distributor hasn’t sheared the pin and lost timing. Although typically even bad timing would be giving you pops and backfires if everything else was good.

To check timing:
Bring #1 cylinder (closest to the radiator) to TDC on the compression stroke and check the rotor’s position. It should be pointing to #1 tower on the cap.

With everything good electrically it is time to concentrate on the fuel.
Before you order the carb rebuild kit check the fuel flow to the carb to make sure it is sufficient. Pull the line going to the carb and see if you get a steady stream of gas. There should be a filter at the carb as well to check. If you don’t get a steady stream at the carb, after that last filter, then you have a restriction somewhere before the carb you need to address.
Typical issue with these older tractors is rust in the fuel tanks. It flakes off and tends to clog the screen on the control valve at the tank. Another gas related issue they have is the gas cap vent can become clogged and create a vacuum that “holds” gas in the tank and won’t allow the fuel to flow in the lines. That might have been your problem when you had the tractor die after ~40 minutes of work and then could restart after some time.

- Mark

Hi Mark and Will,

I checked fuel flow and timing and all is good. Got the carb rebuild kit and started removing jets and found a small brass piece behind one of the jets. Looks as though it was the remains of a jet that was drilled out previously. I was able to get this removed and replaced a variety of parts. Once all back together, she fired up. I need to make some carb adjustments but think this problme is solved. Thanks for all the advice, I couldnt have gotten this done without the guidance.

Dan