Massey Ferguson 65 won't turn over

[Slooby]

For a bit of a change this weekend we've been having some fun and games with our MF65 going from working fine to being dead in a very inconvenient place.

Brother-in-law was taking it out to go do a bit of mowing, hasn't been run in a month or so but it started up fine, he drove it over to the field and then backed it and the topper up tight against the gate post and electric fence partitioning the field off for tge horses. For whatever reason he stopped the engine to engage the PTO drive and went to restart with it out of gear...and nothing...no click, no starter stuter, nothing.

I went out for a peek and the starter switch (stock Lucas 128SA) didn't feel quite right, and dvm told me the battery was low, so battery on charge and removed the switch to take a look at it. Cracked the switch open and all the contactors were black so I gave it a good clean out (fair bit of corrosion) with sand paper, contact cleaner and in the ultrasonic bath, before assembly with some ceramic grease on the shaft.

Battery fully charged and switch refitted still nothing. 12.8 V at the solenoid but nothing happening when turning the key. Battery disconnected again, decided to pull the solenoid. The earth to starter ground cable was pretty black and chewed where it bolts to the solenoid, so after a clean up I soldered on a couple of copper washers to at least give the connector some conductive meat to it. All cleaned up and back on, still nothing. It was getting dark so I gave up and decided to have another look this morning.

Thing is the tractor and skid topper were blocking the only way into the field, which the farmer growing a hay crop in the far bit needs to get out to so they can collect their bales.

So this morning out to it again with the dvm, continuity through all the wires, starter switch and neutral switch, but when put on to ignition field winding no voltage registered, there's continuity on the solenoid winding, just it won't draw anything.

Trying a flying lead straight on to the solenoid winding instead of through the starter did nothing, not even a spark, but there is continuity between it and the ground. This is a replacement solenoid, about 15 years old now, running the test off the tractor on a battery and the solenoid doesn't pull in the plunger. It would suggest that the winding has died, just odd that it has continuity, I was expecting it to be open circuit like the original which I dug out and tested just in case. But I find it strange that it went from working fine to dead in a few minutes.

Thoughts anyone?

Meanwhile JCB roped in to extract the topper on the forks, and then with that out of the way tow the tractor back into the yard, unblocking the gate

[hair bear]

Could have shorted between the windings so you have a circuit, just not through the whole coil. If it was unknown to be getting suspect, the last start could have caused heat to short it hence a sudden failure.

[Slooby]

Cheers Rob, the failure mode was certainly sudden rather than gradual and what you describe would certainly explain why I'm seeing continuity but no draw when engaging the switch.

Having no relays or fuses of any type and everything direct wired is certainly interesting!

Currently looking for a genuine Lucas solenoid over a generic of (even more) dubious quality

[hair bear]

Once you've got it going it might be worth checking that it's charging ok. If the battery was a bit down it may have needed to turn the engine for longer causing more heat to be generated in the windings and a fail.
It could of course be a lot simpler than that!!!

[Slooby]

The charging circuit is long dead I'm told...with no electrics beyond the starter, no lights fitted, and I don't think a functioning glow heater on the inlet

Judging by the mess of a loom (which is mostly Massey Ferguson red by the 'dash' and grey around the engine, or covered in oily dirt) state of the connections on the dynamo regulator box this doesn't surprise me...

I think I should make up a new loom, or buy one as they seem to be about 30 quid...

[Slooby]

It must be said by the time I was roped in, to dig out my Noco charger and connected it up, the charger claimed that there wasn't even 25% charge in the battery...my dad and brother-in-law can be a bit lazy when it comes to maintenance, mostly because my dad (an old school mechanic and marine engineer) is a firm believer in taking "if it ain't broke..." to the extreme with his own stuff, while the brother-in-law simply doesn't seem to grasp what grease nipples mean...and that stuff should just work.

[hair bear]

If you're considering going that far, you could flip it over to -ve earth and fit an alternator.

[Slooby]

The thought had crossed my mind...I did it with my '68 Mini back in 1993 when I fitted a radio

[MrF]

Ive had batteries go bad so that they still show a working voltage when charged and the smart tester's diagnostics say is fine, but they completely wilt when asked to supply cranking current and do nothing, and it was one day the battery is good, the next completely ruined. You can get old school battery testers that have a massive dummy load they drain the battery with to check performance under load, but I just swap the battery out for another one to diagnose here. I have in the past connected a external battery right onto the main starter studs with jump leads just to diagnose that the starter itself was ok also.

I would just -ve earth it by default, it helps with galvanic corrosion if nothing else. I did this to my pony as the first job along with converting it to 12v and fitting a alternator in place of the dyno and the unreliable regulator box. On that the starter solenoid is just a block of copper you pull into contact with a lever connected to a bowden cable so even weirder a setup. But as its not your tractor, you might not be wanting to take it on as its more work, and not something I'd volunteer my time to spend making others lives easier in the long term.

[Slooby]

We did test the solenoid off the starter with flying leads on both it's own battery and another and it didn't pull the plunger in with either so we're pretty sure the solenoid is dead.

There's buggerall wiring on the '65 and it looks like an alternator kit for it is around 100 quid including the alternator, pulley, mounting bracket, a new loom and a new starter switch. Add 30 quid for new solenoid and it's not the biggest job to do, certainly enough to keep my dad and nephew amused...