MF 65 no fire?

[lipripper]

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]

Renew the capacitor in the distributor and then check further.

 

[amaxwell]

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]

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]

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]

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]

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]

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]

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]

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.