MF 65 no fire?

lipripper · Oct 4, 2015

I've had an MF65 gas burner for a couple years now. This summer it started acting up on the fuel side of things. Got that straight and running like a champ again, for about a week. Than it was backfiring ( which had been rectified by adjusting carb, but not this time)
By the time I got it to barn it wouldn't throttle up without blasting me off the seat, so I babied it home( the barn is about 1,000' from where I was at the time)
So I rechecked the fuel side,good to go. Changed all plugs(which were covered in unburnt fuel) ,wires, dist cap,points,condensor,coil,etc. It is a 12v with a resistor between coil and ignition.
Here's what I did to try to isolate the problem
Checked voltage from neg on battery to pos on coil;got 12ish volts
Put test light on between battery pos and distributor back to coil wire. Turned motor over with only faint volts( light )coming thru tester.
Checked resistance in the resistor-2.2-2.6 ohms

I've been lost since I began the elec side of things, with all the 6v-12v combinations of parts that were leftover, or left out, or ...........??

Still appear to be getting no fire from plugs. I've heard of "jumping time" on an old 350 Chevy,etc, and wasn't sure how they fixed it or why it happened.
Silly question, but I gotta ask before I go any further with this," If the tractor is out of time, wouldn't a spark plug still light up, just not at the right time..........
Or would the lack of timing in distributor points for each cylinder keep em from lighting up?"

I am outta time(not just the MF) and about outta weather to wrap up some stuff before winter sets in. Any and all input is welcome.
Thanks

doxford jim · Oct 4, 2015

Renew the capacitor in the distributor and then check further.

amaxwell · Oct 4, 2015

I would replace points , condenser, distributor cap ,and rotor and make sure the coil is working properly . It is possible to have jumped time ,but not likely.

Kenneth S · Oct 4, 2015

You really need a volt meter on the battery, and crank it to see how far down the voltage goes, you could have a battery going away. You can also "hot wire" the coil to see if it will start (run a wire from the + of the battery directly to the + of the coil) then try to start it (don't forget to unhook the "hot wire" if it doesn't start), hook it up only when trying to start, you will need to pull the hot wire to shut if off if it runs so make it easy to unhook (better to unhook it from the battery).

lipripper · Oct 4, 2015

Guys thanks for all the replies..
Kenneth, thanks for the "hot wire" suggestion. Couple questions about that.
1) If the tractor starts with the hot wire trick, what do I need to replace in order not to hot wire it? Ignition relay?
2)What to look for if that doesn't start it? A new coil?
I've replaced the coil twice, and when I put a voltmeter to side of coil from ignition, I'm getting 12v +/- a few tenths.. On the side of the coil returning from distributor, I get erratic 0.2-0.4 volt readings.
I will stick the meter on the battery and see how much it draws down while cranking. Once again thanks for the suggestion. I'm gunna go try right now!

Amax, I have replaced all you have mentioned, and during my internet searching there was a way to test coil, I just can't remember as there were so many different scenarios. I'm gunna try hot wiring it as mentioned above. Would that be the test, if it starts or not?

Doxford Jim, is the capacitor you mention the same as the condensor mentioned by others. It's just a small "can" that fits in the distributor. If the same, I've done that to no avail.....??

A little more history of this tractor and my tinkerings. Whatever I have been replacing, I've been as careful as I can to put back in the same parts I removed.(ie-12v coil with 12v coil, clip on distributor with same,etc.) This tractor still has a voltage regulator,which I thought got removed in the 12v conversion? I have not replaced it yet as I thought that was on the charging side, not the firing side. But that's why I am seemingly begging for answers, as I have researched this for a month now, but it seems there are/were several ways to do the conversion. The ballast/resistor ( I've seen it called both ) is still wired between ignition relay and coil, which is another part I thought would've went away during the 12v conversion. At this point I have left it alone as the coil appears to be getting 12v from it the way it is, although I believe it is wired to pos of coil, neg post of coil runs to and from distributor..
Guys, thanks again. this ole Massey ran like a top until this summer, when it started the backfiring, which is why I'm hesistant to replace or remove any components that would have been removed if they did the 12v-6v in the manner I have read on how to do it.
Lemme know what ya got . Thanks

doxford jim · Oct 4, 2015

Just a thought - have you checked the timing at all ?
Yes - capacitor and condenser are the same thing (different names).
There is an insulated washer when the points are changed, that must be installed correctly. Have you determined this is correct ? Did you replace the points at all ?
Timing can cause the backfiring as can out of adjustment valve clearances (tappets). These could be checked when checking the timing.

lipripper · Oct 4, 2015

Ok here's where I'm at after today's tinkering.

Yes I did replace the points,but didn't remember removing or replacing an insulated washer. And the kit did not come with one.Does it go beneath the points, above them?
All those ?s are relevant, but today I did the " hot wire " jump from battery to coil as mentioned above, to no avail.

No spark from a plug removed(as if I was testing for spark at plugs) and "jumper wire" to coil.
No spark coming from coil wire to distributor ( the bigger wire that is like a spark plug wire ) no matter how I try ( jumped or regular wired)

With volt meter on pos of coil and grounded, with key on=12.4v.......... While cranking dropped to 9.3-10v.
Resistance between pos and neg of new(and old) coils were 3.4ohms
Resistance between the in and out (?) of the resistor before coil =2.2ohms

I have no idea what ohms/resistance/ or any of that means, had my neighbor helping me.

Getting close to calling the ole "mobile mechanic" and pay him by the hour to unfangle things.
Still have a pertinent question>>>>>>> When I removed the distributor to replace points, I was pretty careful to put every back in the same order(firing order,points at same cam on dist,rotor button pointed at same wire,etc), although I could've missed by a mile.. If I missed by a mile,would the coil not fire? Or would the fire stop at dist? Any more ideas are welcome

Kenneth S · Oct 5, 2015

The "hot wire" just bypasses all the tractors wiring, for the ignition, and ignition switch. Have you tried another new condenser? I've seen new condensers that were bad right out of the box. On another note even if it was out of time it would still fire, and since there is no timing chain on this engine its probably still in time. Have you turned the engine over with the distributor cap off to see if the distributor shaft turns?

lipripper · Oct 5, 2015

Yes sir the shaft does turn. I talked to our mechanics at work and they did tell me if it was off time most of the time it would 'spark' but 'fire' , or if I was off by a tooth it may not spark at all. I'm all over the board here??,,,,

doxford jim · Oct 6, 2015

Sounds like you need to check the timing on that engine. It is easy to do, but you need to get the correct info from somewhere.
Usually set the engine to firing stroke on cylinder #1. There should be a hole in the flywheel housing where you can see the flywheel markings. It is a long time since I have done one, but remember the hole being on the left hand side facing forward and located on the front of the casting - might have a rubber plug in it. There are two positions where the cylinder will be TDC, you need the firing stroke (when valve clearances are both slack). I am sure other will be better at explaining than I.
You really need a manual for this tractor as it sounds like you don't have one. It will pay for itself the first time you use it. Check out the link below:

Massey Ferguson Tractor Manuals - Tractor Repair, Service and Parts Manuals

It will probably set you back around $100, but will be well worth buying.

Hope this helps. You should be able to sort this out as it is basic maintenance - not rocket science. Keep at it, you will get it eventually.

doxford jim · Oct 6, 2015

Tractor Manual Search - Yesterday's Tractor Co.

Soundguy · Oct 6, 2015

did you replace the correct coil. there are coils that are marked 12v that need a resistor, and there are coils that are 12v that do not need a resistor. if you put a coil not needing a resistor in a system with a resistor, you may have weak spark.

if the coil is correct and you can run it hot wired.. then check your wiring and connections from battery to key, and thru resistor.

lipripper · Oct 6, 2015

Thanks all for the help. Actually I have 3 manuals for this tractor ( well, for a Massey Ferguson 65, not necessarily my doctored up one ) Two of the manuals are for LP and diesel models only, and the 3rd has only 6v info in it. I did get a manual on CD to put in my computer also, which is the closest I've got so far as to the actual make-up of mine, but it appears to be a "bootlegged" copy and the print is horrible. Thanks for the links to some more, eventually I'll gather enuff to put Humpty-Dumpty back together again!

Soundguy, it will not run hot wired, which I believe eliminates the resistor. Could that mean I bought a coil that needs a resistor and it is getting too much juice?If so,would it spark anyway?
I'm about sold on the out of time problem(only becuz I've tried everything else),and that will be next weekends project. I just can't wrap my mind around the notion of the plugs not getting juice, in time or out of time.In my mind I thought that timing was an issue of spark and fuel not being at the same place at the same time, not no spark at all, although I've been wrong more than right!

Soundguy · Oct 7, 2015

a 6v coil will run on 12v, but it will heat and eventually thermally damage the coil and points... so if it won't run hotwired, AND you have checked that the points are opening and closing, contacts are good, and that they are not shorted, then I would look at timing. Many times a jumped time one will backfire

Jerry/MT · Oct 8, 2015

lipripper said:
Ok here's where I'm at after today's tinkering.

Yes I did replace the points,but didn't remember removing or replacing an insulated washer. And the kit did not come with one.Does it go beneath the points, above them?
All those ?s are relevant, but today I did the " hot wire " jump from battery to coil as mentioned above, to no avail.

No spark from a plug removed(as if I was testing for spark at plugs) and "jumper wire" to coil.
No spark coming from coil wire to distributor ( the bigger wire that is like a spark plug wire ) no matter how I try ( jumped or regular wired)

With volt meter on pos of coil and grounded, with key on=12.4v.......... While cranking dropped to 9.3-10v.
Resistance between pos and neg of new(and old) coils were 3.4ohms
Resistance between the in and out (?) of the resistor before coil =2.2ohms

I have no idea what ohms/resistance/ or any of that means, had my neighbor helping me.

Getting close to calling the ole "mobile mechanic" and pay him by the hour to unfangle things.
Still have a pertinent question>>>>>>> When I removed the distributor to replace points, I was pretty careful to put every back in the same order(firing order,points at same cam on dist,rotor button pointed at same wire,etc), although I could've missed by a mile.. If I missed by a mile,would the coil not fire? Or would the fire stop at dist? Any more ideas are welcome

I'm perplexed why you have a resistor with a 3.4 ohm coil. if the resistor is in series with the coil than the total primary resistance is 5.6 ohms total and your primary current would be around ~2.2 amps instead of ~3.6 amps and that would lead to a weak spark. As the resistor heats up, the resistance increases and reduces the current even more. You do not need extra resistance with this coil as it is a "real" 12 v coil. A "12 volt coil that required a resistor" would have~ 1.6 ohms resistance

I would pull any plug wire and hold it near a good ground and with the ignition switch "ON" , crank the engine over. You should see a FAT, BLUISH-WHITE SPARK, the color of lightning. Anything less is a poor spark then pull the resistor out of the circuit , connect the remaining wires and repeat. Did the spark change?

You say you removed the distributor so make sure you got the timing correct when you put it back in. If you don't know how to do this, ask an I'll give you a simple procedure to do that.

Kenneth S · Oct 9, 2015

I told him to hot wire the coil directly to the battery, still no spark what so ever when cranking. It's either a bad coil, something in the distributor, or a bad coil wire. Something else to check, make sure the wire going from the points to the coil is not grounding out somewhere.

Jerry/MT · Oct 9, 2015

Kenneth S said:
I told him to hot wire the coil directly to the battery, still no spark what so ever when cranking. It's either a bad coil, something in the distributor, or a bad coil wire. Something else to check, make sure the wire going from the points to the coil is not grounding out somewhere.

OK .Check the ground at the battery and at the distributor. Make sure the points are not burned, corroded, or oil covered and are opening and closing.

lipripper · Oct 12, 2015

Jerry/MT I'm with ya on the resistor in the wiring to the coil, but I left everything the same as it ran like a top. My shop mechanic ( we do underground utilities and grade(road) work and we run Caterpillar,but) he is an old tractor fanatic so I pulled him to the side and got the lowdown. What I believe I'm gunna do is pull the generator/voltage regulator and associated BS, run a straight 12V alternator, do away with the resistor, replace ignition relay,and reset the timing.. Thanks guys for all the input.