Starter Motor?

[Andrew77]

Hi

I have an issue with the starter motor not engaging. The battery is fully charged. When I turn the ignition key to start the engine, the starter motor does not kick in. I have tested the yellow wire coming from the ignition at the starter motor end - when the key is turned the tester lights up, so there is power. I think this means there is an issue with the starter motor, or the thing in the picture?

I do not know what the part in the picture is - can anyone identify it please? The yellow wire coming from the ignition is connected to it, the wire is then connected to the starter. The wire on the left is earth/ground, the centre yellow comes from the ignition. The wire on the right is live. I have cleaned all the wires.

Please can anyone help solve this issue? Any advice is much appreciated.

Thanks

Andrew

[DFW_IE]

On other cars I’ve worked on the starter solenoid can get stuck- if you tap it with a hammer a few times it can help it get unstuck.

That part looks like a solenoid.

I have an older 912 and the solenoid is on the starter. Not sure about newer cars.

[Andrew77]

Thanks for replying.

It is separate from the solenoid, and is attached to the body of the car, with wires going to the solenoid. It is in between the ignition and the starter motor, but is completely separate Do you know if your yellow wire from the ignition goes straight to your starter motor trigger switch? This one doesn't...

I have tried tapping the starter motor with a hammer, but no joy.
Do you have any other suggestions?

Thanks for your help.

[Andrew77]

This is another photo that might be clearer.

Thanks,
Andrew

[Tony V]

Andrew,
Search on “hot start relay”, it will give you some insight into what you’re referring to.
If you do replace the starter, consider one of the light weight, high torque units. Much more robust than a rebuilt Bosch unit and smaller so install is much easier.

[Andrew77]

Hi,

Thank you very much. I am guessing that's what it is, but I had to remove it as it as stopping the car from turning over. The starter motor on the car is made in China, so I intended to replace it with a Bosch one, but if there is a different one you could recommend I will take a look.

Do you think the car will be fine without the hot start being attached?

Once again, thank you very much for your help.

Andrew

[mochaSC]

+1 on the high torque starter motor. Easy to install (smaller) and seems well made. I had an OEM starter unit on mine and the wiring was straightforward to go w/ the high torque. It has a reduction gear and it sounds like its barely working to spin the motor. Such a change from the OEM unit which seemed like it was working pretty hard to crank. I put one on my 66 912 and also my 82 SC and it has worked great.

[mochaSC]

only possible issue with the high torque unit is "clocking" the mounting plate. You can see where the adjustment holes are located where it attaches to the bell housing. I have heard of some units requiring adjustment to fit. not a big deal but just wanted to make you aware. Mine fit great x2 right out of the box.

[DFW_IE]

Originally Posted by Andrew77

This is another photo that might be clearer.

Thanks,
Andrew

Sorry to have misled you- yes this picture clearly shows the starter solenoid. Looks like you are now on the right track.

[Bob Ashlock]

The starter solenoid is mounted ON the starter. It is the cylinder with a winding and "plunger" that engages the starter gear to the flywheel gear teeth while simultaneously activating a contactor switch inside that connects the battery to the actual starter motor. What goes wrong is that the plunger gets sticky and drags in the cylinder. Often the external relay is added which helps give more current to the solenoid allowing it to overcome the drag and actuate the contacts that power the starter motor.
In my opinion this is unnecessary. I have taken the solenoid off the starter, disassembled it enough to clean and lube the plunger with some slippery moly grease that won't harden with heat. Once the plunger can slide freely it will slam the contactor closed just as new again. No need for an external hot-relay fix.

[WFBowen]

+1 with Bob Ashlock’s post. Sometimes it’s just as easy to fix something than to patch the problem.

[Andrew77]

Thanks for all your help everyone! Much appreciated.

Andrew

[wkrtsm]

I liked the reply about "you just have to tap on the starter to release the solenoid". I would recommend replacing the starter with a hi-revving lightweight starter - exactly like the one pictured by mochaSC. The OEM starters are too heavy for my personal taste.