Ford 860 starts fine, but starts sputtering after a couple minutes

[cbrake]

Hi, having some problems with my Ford 860 ...

Lately, it starts great, but then has been sputtering and backfiring soon after starting. I replaced the plugs and points, and it seemed to run fine for several sessions, including a hour of so of heavy pulling grading 1/2 mile lane. Now it is back to its old tricks.

The generator was weak, so I would have to charge the battery every couple months. I installed an alternator and new wiring harness thinking a slightly higher voltage might help. No change.

Gas flow to the carb seems good -- I've unhooked the line past the filter and run gas into a can for several minutes without any noticeable slowdown.

Spark seems weak (with spark tester) -- I need to do some more testing tonight after it is dark enough to see the spark in the tester.

Here is a video of it starting and then having problems:

Shared album - Cliff Brake - Google Photos

Appreciate any suggestions -- it is a great tractor when it works -- exactly what we need. But, these intermittent problems are proving difficult to solve.

Thanks,
Cliff

 

[Ford850]

Other than poor spark, you can check for a dirty/plugged air filter, stuck choke, or carb that's out of adjustment or needs cleaning. Can you remove the drooping hose from the air filter to see if it runs smooth after it acts up?

 

[Roadworthy]

There are probably a number of things that can cause your problem. Check your timing. Does it have a vacuum advance? The flyweights in the distributor could be sticking. You may have a small crack in the distributor cap allowing a bit of moisture in. The rotor could be shot. The coil could be getting hot and going partially open. Figure on spending some time tracking this one down.

 

[cbrake]

Thanks for all the ideas ...

Removed the air filter hose -- no change.

Check spark with a spark gauge between wire and plug -- spark is intermittent and stops when engine cuts out.

If I start engine, it will sometimes run for a few seconds, and sometimes run for minutes before cutting out -- very odd.

Sprayed off the inside distributor cap and rotor with carb cleaner (was a little oily) -- no change.

Replaced condenser with an old one I had laying around -- no change.

Replaced coil with an old one I had laying around -- no change.

Rotated the engine until the points were closed, turned on ignition and measured current through coil -- 5A. This seems a little high. I left the current going through the coil for several minutes to see if it would open up -- it never did.

The alternator kit I got came with a resistor -- if I add the resistor in the circuit with the coil, I only get 2A through, but engine will not start with the resistor in line with coil.

It appears when I got the tractor, it was set up for 12V but there was no resistor in line with coil -- I wonder if I have burned up both my coils? Perhaps there are melted windings or something so it is not generating enough voltage? The fact that I never saw the coil open up does not fit with the intermittent spark.

When it cuts out, it seems all cylinders quit -- so it seems the problem is not the plugs or plug wires, otherwise there would be times when one or my cylinders cut out.

Today it was running really good for several minutes once -- would rev up and sounded pretty normal.

Next ideas:

- check spark between spark plug wires and head when engine cuts out -- eliminate possibly of spark plug issues -- I don't think this is the issue because they all seem to cut out at once
- replace ignition switch -- it looks like a quite old toggle switch
- try new coil and condenser

I have not checked timing yet -- could that produce intermittent problems like this?

There is some slop in the distributor shaft -- I suspect the bushing is worn, so could try a rebuild or new distributor. Not sure I'm up to replacing the bushing in the existing distributor.

Ideas welcome as this one has me stumped.

 

[kf4uda]

If my 861 sets for a while sometimes the float will stick in the carb, starving the engine for fuel. I take a wooden hammer handle and “lightly” tap the carb bowl. Some day I am going to actually clean it.

Might be worth a try for you.

 

[cbrake]

videos of the points and play in distributor shaft:

Shared album - Cliff Brake - Google Photos

Shared album - Cliff Brake - Google Photos

The ford shop manual says min shaft dia is 0.4665" and max bushing dia is 0.471" -- the diff is only 0.0045"!! Looks like I have a lot more slop than that.

So, inclined to put a new distributor in it, or get the one I have rebuilt -- any opinions what is the best route?

Only $93 on amazon: Amazon.com: 86588846 Ford Tractor Distributor 5, 6, 7, 8, 9, 51, 61, 71+: Industrial & Scientific

but make in China.

Guess I should call the local Ford dealer and see what options they provide.

Also, would like to get a new coil -- any thoughts if the high voltage variants are worth the extra cost?

 

[Ford850]

Here's another option for parts.
Ford 800 Parts - Electrical System Parts

 

[square1]

You mentioned the ignition switch. That was the issue (53 Golden Jubilee) when I first got it. Would run fine and then die. Check the voltage through the switch after it dies.

 

[LouNY]

Check the polarity of your coil, with the alternator you are most likely negative ground,
the coil negative needs to go to the points. Also be sure the points ground is good.
To monitor the power to the coil you can tie in a small light bulb in parallel with the power to the coil.
When she is running how hot does the coil get.
You may need the full 12 volts when cranking to start then go through the resistor when running.

 

[cbrake]

Thanks for all the ideas. A local shop had an aftermarket distributor in stock, so I put that in. I had trouble getting it to start at all (but could have been timing). Noticed the spark plug wires were the graphite core, so I replaced them with a set of copper core I had purchased but never installed yet as the old wires still looked good. After replacing the wires and messing with the timing some more, it started and runs great now. Idles very smoothly and has lots of power -- even at very low RPM. I'm not sure if the distributor or wires is what made the difference, but at any rate, it is running good now, and since the slop in the distributor was way beyond what is allowed in the service manual, figure it is time to replace that anyway.

Thanks for the note on the ignition switch -- plan to replace that soon too as it looks quite old.

Still need to figure out the coil situation -- currently running a 6V coil marked to run without resistor at 6V on a 12V system, which is not right. Will try again with a resistor now that plug wires and distributor are changed. Some time back, I ran an experiment where I adjusted the engine to where the points were closed, and measured current through coil (5A) as noted above. The current kept flowing and never cut out -- after several minutes, the coil never got hot to touch.

Thanks for all the ideas -- glad it is running again!