Joined: Aug 2017 Posts: 952 Threads: 38
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If it runs in the reverse direction the internal connections in the starter are wrong.
Putting negative or positive through the starter terminal will not reverse its rotation .
Does it have the correct pinion for the starter, if you have a forward pinion on a rear starter it won't throw out, they are different. First check is to see which way your starter is spinning , viewed from the pinion end it should go anti-clockwise . In other words opposite the direction of the flywheel.
Joined: Oct 2017 Posts: 1,536 Threads: 55
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This reminds me of our second RN saloon where the starter wasn't connected to the very large battery behind the passenger seat because the cable wouldn't reach it. The engine started easily on the handle so it was a few weeks before I bought a battery that would fit in it's rightful place. With it connected it spun the engine over but the engine wouldn't start, then I spotted the fan going the wrong way. As an immediate fix I fitted a spare starter and some time later I raised the question with John Platts who told me they didn't know how to fix it but they had a later 4 speed starter which went the wrong way. I took this and swapped over the parts between the two starters so I then had a 3 speed and a 4 speed starter both of which now ran the correct way and sold latter. So it's not unusual for starter bits to be mixed up. I'd bench test the starter with it securely clamped down in a vice to check it's direction of rotation and to see if it has the correct bendix helix.
Joined: Apr 2018 Posts: 192 Threads: 76
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Well, I finally got around to taking the starter motor off and the good news is that it definitely rotates the correct way.
I did try adjusting the pinion retaining clip but the real issue seems to be a lack of acceleration when the motor is powered. Looking at the relatively small mass of the pinion gear it looks like it would need the motor to accelerate quite violently to get it to move along the helix which I think is what Nick Turley was suggesting.
The brushes seem to be bearing on the commutator OK but now that I've taken them out they are certainly worn although the face which contacts the commutator is still nice and square to the rest of the brush.
I'm going to replace the brushes anyway but is this likely to be the cause of the lack of violent acceleration or is there anything else I should be looking at?
John.
Joined: Nov 2017 Posts: 562 Threads: 56
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Location: West Yorkshire
Car type: Type 65 1934 + RP 1932
It sounds like a dry joint somewhere. In the first instance I would stick 12 volts across it in order to confirm your 6 volt battery has enough oomph and you are not suffering voltage drop by using insufficiently beefy wiring in your bench test.
Joined: Apr 2018 Posts: 192 Threads: 76
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Colin,
I didn't actually disconnect the motor, I simply unbolted it and laid it on the floor then re-connected the direct to battery earth connection and tried operating it.
The battery and cables are all new but this does mean that on the positive side the starter button was still in circuit and on the earth side the battery isolator was also in circuit.
I've just tried measuring the voltage between the positive and earth connections to the starter but without the starter actually connected and this is 6.2 volts which is almost the same as across the battery so I don't think it's volt drop although I suppose the situation may be different under load.
John.
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27-05-2020, 01:57 PM
(This post was last modified: 27-05-2020, 01:58 PM by Steve Jones.)
I bought a similar starter motor from Tony some years ago on a 'not tested, bought as seen' basis. When I go it home and tested it clamped in the vice it turned OK but not well even on 12v. Strip down, clean it all up particularly the commutator and fit a new set of brushes and it was back to where it should be. It's been starting my Trials Car without problem for the last 10 years or so.
That you were able to test yours as you did with it laying on the floor says there's something wrong with it. If it was working properly and you'd tested it this way you'd understand what violent acceleration was!!
Steve
Joined: Nov 2017 Posts: 562 Threads: 56
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Location: West Yorkshire
Car type: Type 65 1934 + RP 1932
Hi John
I'm sure Steve's advice is good. However, if you still to have problems I would take the isolator out of circuit. I had one of the red key jobs on our boat, which showed continuity with a meter but failed under load. The memory lingers on as having "proved" it OK I spent ages checking everything else!
Good luck,
Colin
Joined: Aug 2017 Posts: 1,474 Threads: 26
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Location: North Yorkshire
I've fallen for that one as well, Colin; on my old Trials car. Damp gets between the two copper contact faces and causes corrosion. Continuity when tested but breaks down under load. Easy to diagnose when you know it can happen. Knowing it can happen rather more difficult to learn!
Steve
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OK, I've now got some new brushes from Seven Workshop and I've just cleaned the commutator with a rag soaked with some carb cleaner.
The commutator looks fine although obviously it could have an electrical issue.
Before I finally reassemble it and do a bench test is there anything else I should do?
John.
Joined: Aug 2017 Posts: 783 Threads: 26
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Location: On a hill in Wiltshire
Clean out the gaps in the commutator if you haven't already done so.
The standard tool (if, indeed it will fit) apparently is an old Junior hacksaw blade.
