Testing starter motor

I have bought a "used" but as new starter motor.

Do you know how I can test it without fitting it?

 

Jump leads and a wire 12v car battery
Best in a vice or something to hold starter

And you will sh!t yourself when it moves

Jump leads to starter black to case red to big terminal on back of starter wire from red lead to solenoid this should not be attached sort of flicked to activate solenoid and starter will rotate thats how I would do it

 

The unofficial way we used to test was to secure flange in a vice spin it up with a battery and try to stall it with a lump of wood, old wooden tool handle etc. Of course with regard to H & S procedures that would be a no no nowadays.

 

As I understand it, the starter only has one bearing and depends on the bushing in the bell housing to support the shaft. You therefore need a test jig or a spare bellhousing to test one away from the vehicle.

 

^as above. You can just give it a quick dab to see if it twitches. Don't run it for longer.

 

Are you sure it's a starter motor Andy?

 

When I asked this a few weeks ago everyone said it couldnt be done because of the bush requirement. Looks like it possibly can now just not to run it for long. Im going to try it now on the extremely rattly one that has just come out of my bus. Will let you know how I get on

 

The main shaft in these starters is live mate!! All the brass bush does it stops it earthing on the case and supports it at the same time bud I tested mine with them little lift batts I got

 

I was surprised when I was being told it couldn't be done too but there we are. Its going to happen!

 

It can be done, but if you let it run the armature will grind everything else to pieces as one end isn't supported.

 

I bought it as one...... It bloody better be

 

Brass is a rather good conductor- you’re right it supports the shaft but it doesn’t stop it earthing.

 

Would that still be the case without a load (i.e, flywheel) on the pinion?

 

It whizzes round, fella - surprised you haven't tried it. If you operate the starter while it's on the bell-housing, but without the engine, there's a healthy clack of the solenoid then it goes like the clappers. Most entertaining. It's like a cuckoo clock, but with a pinion on the end, obviously

 

I meant would it damage the starter spinning unsupported at one end but without any load on the shaft from the flywheel?

 

Dunno. I wouldn't power one up unsupported whatever...it'll chew the armature up.

 

Because of the "series wound" design of a starter motor it will wind itself up to the point where the speed and friction balance. Basically if it doesnt rattle around or engage in a flywheel it can theoretically spin up to speeds where things burst.
The easiest way and safest way to test it is on an engine. Its only two bolts and a couple of wires..

 

Tested it out of van. Phookin scary but does spin up. Once it was out it was clear to see why the starter had not been operating properly. Replacement Bosch £67 quid.

@AndyC if you need to check out my other post regarding taking the bush out with the engine in. That can be done too. I will post up the tool I will use to replace the bush after I have made it and tried it today. The extraction tool I made is on that post

 

What was wrong with it?

 

Something had broke inside. When I shook it the whole mechanism smashed from side to side. If I grabbed the nose of the starter it would wiggle freely. Its likely it was jamming probably in the bush. The symptoms were a van that didnt start unless it was push started but the fault was intermittent until last week when it just wouldnt run. Happily all is well now. Very happy. Dont have to choose my parking carefully anymore.