my 73,starter motor intermittently does not crank(no sound at all) when turning key on.jumping two large terminals on starter with key off engages the starter motor, and if i then turn key it will engage starter motor and start car .i just replaced starter switch thinking that was the problem,no change.starter motor is only a few months old.connections to starter motor and ground strap look ok.any ideas.?

You don't jump the two large poles .. you jump between the upper pole (battery lead) and the spade terminal. That causes the solenoid to activate, pull the bendix gear out and supply voltage to the starter motor.

The solenoids on the currently rebuilt starters are by and large an ornamental product (China, Taiwan, etc.,) and are crap.

If the solenoid has burned contacts inside, it will generally do nothing when trying to activate it with a key. Next time, bang on the stater with a hammer and then try the key switch.

Old wiring, bad grounds are also problematic.

getting my hammer out as we speak.

actually,jumping both large poles will just make starter motor go,but this is enough to allow key to work and engage solenoid and start car.so,if banging on starter makes key work,does it mean i have a bad solenoid-even if starter is only a few months old with maybe a 800 miles on it

Inside the solenoid is a copper contact. Repeated contact can burn the copper and make it somewhat non conductive. Sometimes banging on it dislodges some of the carbon and it makes contact again.

On old Chevy starters, we used to take the solenoid apart, clean the copper plate and rotate it for a clean surface.

The motor spinning when you jump the large poles is essentially bypassing the solenoid, but does not engage the bendix to rotate the engine.

Solenoids go bad long before the starter.

And as I stated about rebuilt starters ... some use cheap solenoids and they fail easily.

by spinning motor ,i may be moving it away from flat spot,thus allowing key to start car.i think ill source another starter motor.

I threw away my stock Bosch starters and use the modified Japanese gear reduction starter on all my cars. Used to be $119 on eBay.

I had a Bosch SR68X eat my flywheel teeth.

That's because it should have been an SR17X.

--DD

Wrong Damp Dave .... SR17X is 0.8 kw and the SR68X is 1.2 kw. Porsche used them interchangeability on the 911s. Other than larger in diameter and power they are the same mechanism.

Did '73 models have the seatbelt-ignition interlock? It's still intact in my '74... not only is the starter unresponsive until the driver's seat belt is buckled, it'll even lockout if there's any weight on the passenger seat without the passenger belt buckled.

'73 no ... '74 yes

Another Goubermint clusterf__k! One year only.

yes, my flywheel had been eaten up by previous starter motor.so what recommendations are there for a good starter motor, and where to get it.?

I can get a 914 starter rebuilt at a local rebuilder shop that does good work. $75 rebuild cost, $25 for the starter core I provide him and $15 shipping. Or go with the gear reduction starter Ron suggested.
Bruce

bruce, ive sent you a pm

Wait, does that mean I'm ALL WET?

--DD

following up with my starting problem.got a rebuilt starter from bruce stone and now it starts every time.even though the old starter was only a few months old,there was a flat spot giving intermittent start problems.

Nope .... How many years have you been known as DD (Damp Dave). I always thought it was a statement of your lifestyle.

And I also know you didn't swim here.