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MG TD TF 1500 - Wiring the starter - is polarity important?

One would think that after 61 years of ownership, I would know this.

I recently experience starting problems. In replacing the starter and replacing the battery, it worked fine for a few starts, but then everything is dead! At one point, I found the new battery dead. Did I re-connect it incorrectly?

I couldn't find any image of the connection in the WSM or any of the parts catalogues.

So I got a new switch from ASL. Car is still + grnd. Does the starter wire go to the rt side of the starter switch (looking straight on), or is it reversed?

With egg on face ...

Gord Clark
Rockburn, Qué.
Gord Clark

The generator cares about polarity.

The starter only has one terminal. It should not matter.

If the grounded terminal on the battery says + or POS next to or on it. The battery was installed OK.
But I would start there. Look at the battery and insure that the positive terminal is connected to ground.

If you were to put the starter on the wrong switch terminal, it would run continuously.

Jim B.
Jim B in NJ

GORD.
The starter pull switch does not give a hoot which wire goe on it's posts. One wire from the starter goes on one post. The remaining wire (WIRES) go to the other one.
Polarity is not recognised by the starter.
Sandy
Sandy

Hey Jim,

Good point " ... it would run continuously.".

Perhaps the (internal) contacts have burned open. Putting in new switch tomorrow.

Gord Clark
Rockburn, Qué.
Gord Clark

The starter has perminent magnets, reversing polarity has no effect on the starter, it will always spin in the same direction reguardless of polarity. The switch is a simple contact switch. It matters not which wires go where.
I'd say you got a bad battery, or a constant drain on the system.
F.W.I.W, my TF has a bad starter right now. I have been cranking it. See you in Stowe in a few weeks! The NEMGTR has a tent this year, come check it out! I've invited the chairman from the B register to join me, he is arriving from Colorado.
David.
D. Sander

Gord, Check the switch by loosening one of the cable coupler screws and rotate the starter switch post. This will rotate the contact on the inside providing a new connection. If it starts to work... switch is your problem... if nothing changes... look elsewhere.
... CR
C.R. Tyrell

Who would that be David?
MG LaVerne

Alan Magnusson
Lew3

^ yup
David
D. Sander

LaVerne, you should come to! You could make the drive in a few days.
-David
D. Sander

Thank y'all for help.

I've just come through cataract surgeryand cin't do much. My son-in-law will install new switch this Aam.

Plan to be at Stowe. Greatb idea to have tent.

Sorry for typos - noy my style.

Gord
Gord Clark

GORD.
I thought you drove RINCOLNs
Glad you will be able to see clearly now.
Sandy
Sandy

Haven't seen Alan or his better half in several years. Tell him LaVerne says hey. Love to come David but I just don't see it happening....probably a 6 day drive one way from here in the TF....little less in the B.
MG LaVerne

This starter issue still persists. I installed a new starter switch, a new battery and have changed the starter for Sprite/Midget one. Pull the starter and nothing happens. Horn/lights are strong.

I still have one more fresh starter but its also Sprite/Midget.

Does the Sprite/Midget starter have the same nbr of teeth as the (original) TD/TF?

Gord Clark
Rockburn, Qué.
Gord Clark

Yep same setup Gord. You might have a good look at the cables and particularly the grounding straps on the engine and the battery.

Just My thoughts.
MG LaVerne

Gord, as LaVerne points out, you have some sort of basic connection problem, nothing exotic. Take the battery out of the car. Take the starter out of the car. Connect a battery jumper cable between the case of the starter and the positive terminal of your battery. Now connect another cable to the negative terminal of the battery. Now, with the starter firmly held down, touch this cable to the terminal on the starter. Does it spin? If not, it's bad. If it does you have a cabling problem. The next steps are with the battery and started reinstalled. Bud
Bud Krueger

GORD.
Just pop in the midget starter and pull the knob. If the broken one is the original I bet that the brushes are worn to a frazzle.
Just remember that the barmaid pulled the wrong knob and got STOUT.
Sandy
Sandy

As Bud Krueger said, "Now, with the starter firmly held down, touch this cable to the terminal on the starter."
Man, did I ever get a surprise when I performed a similar test. That starter has WAY MORE TORQUE than I expected. If I were to do it over again, I would put the starter against a wall and hold it in place with foot pressure or chuck it up in a vice!
Jim Merz

These things are beasts indeed. But the try to crank the car by hand to the speed that the starter achieves - those are the forces you have to deal with.
Bud's message should have read FIRMLY!
Rgds Mike
Mike Fritsch

Still fighting with this. I'm about to install my 3rd starter.

Connected a brand new battery across a brand new starter switch, still dead. Everything else works - lights, horn, etc.

So tomorrow I will install yet another starter (I have several!). For you fit folks, sounds easy, but I have a back that just won't cooperate.

Going nuts. We're experiencing absolutely gorgeous (windscreen-down) late summer weather whilst my TF is immobile.

Gord Clark
Rockburn, Qué.

Gord Clark

Gord,

If you have a known "good" battery and starter, then the issue has to be somewhere in the wiring. I'd suggest that you use a good set of battery cables and run one lead directly from the battery ground to a clean connection of your choice on the engine block. Connect the other lead to the hot battery terminal and with the car out of gear and the handbrake on, touch the cable to the hot post on the starter. If the engine spins (and it should), remove the jumper cable from the battery ground and perform the test again.

If the engine fails to spin this time, then the issue is somewhere in the ground circuit. Since you have lights, that would suggest that the fault is the ground strap between the gearbox and the frame.

If the engine does spin, the the issue has to be ...

1. One or both cables from the battery to the starter or switch

2. The switch itself... I know it's new but.....


I believe you told me you had someone who knew her way around an MG. Maybe she might do the concrete while you handle the stand up tasks? :-)


For whatever its worth I've been doing the same routine myself... starter went south and I have 3 other ones of less than desirable quality on the shelf. Worked a couple over to get one use able but I have doubts about how long it's going to last. Not much fun changing one on a TF.












MG LaVerne

Gord, the suggestions that you're getting are important. There are two places under the bonnet at which you don't want to create sparks - one is at the battery terminals (hydrogen gas), the other is at the starter terminal (directly under the carburetors - petrol). It appears that you're not certain that your starter is any good. Test it - all by itself - off of the car - use your battery for power - and a set of jumper cables. Prove to yourself that the battery and starter are good. Then you can start working on grounding, cabling and switch issues. Bud
Bud Krueger

PROBLEM SOLVED - I'm driving the TF to Stowe tomorrow AM.

One of those niggly hard-to-pin-down, intermittent-type faults.

I have a collection of batteries, starters, generators, distributors, etc, so no shortage of back-ups.

I checked all the starters while they were out and sitting on the floor. All seemed to work. I bought two new starter switches from Abingdon. I bought a new 5-yr battery from Wally's World. I played Musical parts with all these gubbins - still the problem persisted.

My daughter happened by. She happens to have 4 English sports cars. She casually suggested that I could borrow a spare starter from her. This time however, I took a wire brush to everything, including the engine block, which I had failed to do on the many previous efforts.

I added star washers to the bolts; tightened the bracket holding the starter switch.

One, or all of those things did it! It sprung to life on the first pull!

So for those of you who, if ever, encounter a similar problem, check EVERYTHING so that the ground circuit is fully made. Don't trust meters or continuity testers. I learned a great lesson from this two-week experience.

An un-restored 60 year-old car collects a lot of crud, and over the years, I failed to deal with that, and paid the price.

See you in lovely Vermont this week-end.

Gord Clark
Rockburn, Qué.
Gord Clark

Problem solved...Yippeee!! Have a great time!
MG LaVerne

Congrats, Gord. Give yourself a gold star. Bud
Bud Krueger

This thread was discussed between 28/08/2015 and 18/09/2015

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