MF ignition

Hook a voltmeter from the negative post of the battery to a clean metal part on the engine. It should read zero. Watch it when you press the start button. Does it stay zero? If not you have identified where the problem lies.

If the voltage stays zero when hooked to the negative post, hook one voltmeter wire to the positive post on the battery and the other to the cable. Often this is where the problem lies as the battery post gets corroded. Clean it well and try again.
 
I researched and found to diagrams that show a 6volt system with both a negative ground and a positive ground. I have power (voltage) from battery to voltage regulator to starter and to start button. However once I engage the shift lever to the start button it drops the voltage.
 
As I said you have poor connections some place. Could be at the battery or at ground or for that matter a bad cable it self which you cannot see. A VOM can read volts even when there isn't enough to spin the starter
 
Be to positive or negative ground it all works the same only difference is how it is grounded but many get confused by it because they over think things.
 
Does it have a solenoid?? If it does make sure it is out of gear and jump across the 2 big terminal with a piece of heavy wire. If it spins over then the solenoid is bad
 
That is a solenoid and it should have 2 posts on it. One would be the battery cable post and the other to the starter. Jump across them
 


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Use a heavy wire and jump across the 2 brass studs sticking up. Be sure it is out of gear.
 
With the picture you just posted it looks like you might have an old Ferguson, not a Massey Ferguson. Post some pictures of the complete tractor and the serial number.

In your original post you wrote "it loses voltage when the starter button is pressed by the shift lever". Please describe where you attached the voltmeter leads when you made that test.

Have you had the battery load tested?

That looks like a new starter switch. It may not be adjusted properly. As old posted, make sure the tractor is in neutral, then jumping the terminals of that switch should spin the starter.

It is possible the starter drive is jammed in the ring gear. Loosen the starter mount bolts until you can wiggle it around.

This post was edited by Jim.ME on 08/02/2022 at 04:18 pm.
 
Both studs on the solenoid its self. Ive always jumped it from the starter. But this starter on has the one post on it.
 
They arent brass they are small silver studs on the coil. The blue item in the picture I sent. The starter is below that with only one connection. The coils is brand new
 
What your calling a coil has 2 cables going to it. One of the 2 comes from the battery and the other goes down to the starter. Short across those 2 and see if it spins over. Be sure it is out of gear
 
Again, how about posting some pictures of the complete tractor and the serial number so it can be properly identified. I believe you have an old Harry Ferguson tractor, not a Massey Ferguson.

The blue ignition coil has nothing to do with the starter circuit, so wires on it don't matter at this point.

You do not have a solenoid. You have a mechanical starter switch engaged by internal linkage connected between it and the shift lever.

When you say it loses power do you mean that if you put one lead of a voltmeter on the starter switch stud the battery cable hooks to and the other to the battery ground, the voltmeter shows the power goes away when the shift lever pushes the switch? If you are putting one voltmeter lead on one stud and the other lead on the other stud, power will "go away" on the meter reading when the lever is pushed, because the switch is equalizing the power on both studs. What is the voltage at the terminal of the starter (one lead on the stud, the other to a ground) when the lever is pushed to start?

Have you had the battery load tested?

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This post was edited by Jim.ME on 08/03/2022 at 03:40 pm.
 
I think you and I are pretty much on the same page to this one and we seem to be talking over his head some how
 
Then your not understanding what I am trying to tell you. The coil is the ignition system and has nothing to do with the start system. The part I am talking about has the cable from the battery to the start switch and then another cable to the starter it self. That is where I am saying you jump across to see if the engine will spin over
 
(quoted from post at 22:11:42 08/03/22) 1 wire gos to the distributor and the other gos to the ammeter.

You are talking about primary wires at the ignition coil.

Does the starter crank the engine over? Yes or no.

Is the problem power is being lost to the coil, when the engine is being cranked over? Yes or no.
 
Yes you can either use a heavy wire and jump across them or take the battery cable side off and touch the other post either way will work to see if it spins over
 
In that case either the starter is jammed in the ring gear or it is bad. I'd loosen the starter and sort of wiggle it to free it up
 
It sounds like your starter may be the problem. As someome else stated, the gear may be jammed to the flywheel. Try taking the starter loose, then put it back on and see what happens. If still the same you may need the starter rebuilt.
 
It must be bad. The starter gear spins free when I move it with my finger. But will just arc when try and jump it.
 
I replaced the starter and that solved that problem. Now Im just trying to get it to start. It trys to but wont fully kick over.

Already cleaned the carb out and did gasket set.
 
Make sure you have a good blue/white spark that jumps a 1/4 inch gap or more at the center wire of the distributor cap and at all the plug wires.

Then if you have good spark pull the air cleaner tube off the carb and hold your hand over the air intake of the carb. You should have a good suction and get gas on your hand. It may even try to start so be sure the ignition is on when you do that
 

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