10 replies to this topic

[mk=john]

Hi, I have a 998 cooper (1966) Mk1 pre-verto. I have added a string about battery jump starting which you may have seen. The starter motor is turning real slow, and I know nothing is stopping free turning of the engine because it was running last week!

The starter is inertia

The starter sounds as if its labouring. Assuming, the battery charge was ok, could my starter be on its' way out? If so, do I need a special starter, as my car is positive earth?

[biggav]

i'd check the battery and all your earth points too!!! I've got very similar symptoms at the moment even though i got a heavy duty battery 3 weeks ago.... though i didn't charge it up when i got it!!!

[mk=john]

Hi, I notice on my car, the clutch cover does not have an earth lead to any part of the body, Is there anywhere else I should look for possible earth connections?

My car is positive earth.

[m1n1]

regardless of the fact it is positive earth, put an earth lead on it, you do need it. then see what happens.
also i doubt the starter motor would be different to any other inertia starter motor.

[dklawson]

As stated above, the starter motor doesn't care about polarity. Also as stated above, put a ground strap between the clutch cover and inner wing. Failure to do so can quickly result in fused choke and throttle cables as they end up carrying all the current for the starter motor.

If it still turns over very slowly, remove the stater and place it on the ground. While holding it down with your foot, tap a set of jumper cables (connected to your car's battery of course) against the stater housing and its hot pole. It should spin up fast and try to jump out from under your feet. If it doesn't, there's a good chance the bearings (bushings) are gummed up and need cleaning and re-lubrication.

[mk=john]

Hi
Minispares website says that many minis had the earth lead from the gearbox to the subframe. Does this sound right?

As for testing the starter by holding it on the ground with my foot, because my car is positive earth, should I hold the red lead on the housing, and the black on the terminal?

[dklawson]

Hi again. On early cars the ground strap went from the clutch cover to a spot on the right front inner wing. There should be a hole there about the right size for a 5/16" (8mm) fastener. Make sure you scrape the paint off the hole on the wing until you have a nice clean bare metal spot to tighten the ground strap up to. Use some dielectric grease on the cable end before tightening it to the wing so minimize corrosion... use Vaseline if you don't have dielectric grease. If you don't find the wing hole I'm talking about (for some strange reason)... buy a ground strap and determine a suitable spot to make a new hole on the inner wing and attach the new cable.

As far as bench testing the starter motor, hook it up like you would if it were on the car. Hook your jumper cables directly up to the car battery. Hook the "ground" jumper lead to the shell/housing of the starter motor. The mounting flange is easy enough to clamp to. Take the hot battery/cable lead and tap it against the hot lug on the starter (where the cable from the solenoid would usually go).

Starter motors are not polarity sensitive. If you contemplate changing the ground from positive to negative on an older car, the areas you have to be careful on are the aftermarket parts like tachs and radios. Beyond that, you have to switch the low tension terminals on the coil and most importantly, you have to re-polarize the generator. If you ever decide to go this route, there are a couple of technical articles on the Mini Spares web site that will walk you through what to do when changing polarity. Anyway, starters don't care so just hook it up as stated in my paragraph above.

[mk=john]

Hi Dave
You have been really helpful with this. As a precaution, I will be putting on a new starter (temporarily)tomorrow, and having the current one rebuilt by a really good auto electrician I know.

I have also purchased a minispares engine ground strap and will also be adding this also. Just as a temporary measure, I will place the strap between the clutch cover and the bolt which holds the brake pipe splitter (bolted to the bulkhead behind the engine) until I make a hole in the inner wing.
Would that be OK if it is temporary?

Thanks

[fikus01]

i woulkd personally not like to earth anything on a car through the brake parts!! even if its just a junction for the pipes!! direct to body for earths every time!!

[mk=john]

Hi Doug
Last night I gave the battery a full charge. This morning, I have fitted an earth strap to the clutch cover and the hole at the front of the inner right wing, an 8mm bolt fits perfectly.

Starter motor is now turning fast! Seems nomalk now and the engine fires up easily.
Thanks for all your help, and also to everyone else.

Ceers

[dklawson]

I'm glad you got it sorted out !