Bosch starter engaging by itself ?????????????

Bosch starter engaging by itself ?????????????

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spatz

Original Poster:

1,783 posts

185 months

Friday 4th April 2014
quotequote all
Hi folks,

I have a funny phenomenom on my yet to finsih canam with a turbo box and a Bosch starter motor.
It seems that starter engages himself when I rev the engine and repeats trying to do so after started
doing so. I removed the starter relay after starting to make sure the starter relay is not doing funny, but
it seems the starter can do it by itself.
the only explanation I have that with reving the engine the alternator goes to its charging voltage which is
maybe an explanation ?
Attached a picture of the wiring.

The brown wire is not running over the starter relay only the red/white. maybe the bosch starter requires
the brown supply wire to be switched by a relay too ?

thanks

Edited by spatz on Friday 4th April 11:43

anonymous-user

53 months

Friday 4th April 2014
quotequote all
Are the engine vibrations at high revs causing that un-insulated terminal to touch the brown wire??

3Dee

3,206 posts

220 months

Friday 4th April 2014
quotequote all
Possible that the toothed gear on the starter is too close to the flywheel ring at rest maybe?
Other than that, it has to electrisical or a faulty unit.

AndreasW

102 posts

160 months

Friday 4th April 2014
quotequote all
What is the brown wire for?
The ground pole of the starter motor and the magnet switch are normaly connected.
So if your engine is properly grounded - you only need the big red cable coming from the battery and the red-white
coming from the starter relay.

Try it with the brown cable disconnected.
I think it is coming from the alternator and should be connected to the big red cable in order to charge the battery.

Edited by AndreasW on Friday 4th April 14:51

spatz

Original Poster:

1,783 posts

185 months

Friday 4th April 2014
quotequote all
very embarassing, the brown wire and red/white were connected to the electrical same terminal
which I missed when wiring the alternator. So once the alternator was giving enough juice the starter tried to engage..........
The correct wiring is brown (alternator charge) together with the red cable from the battery and
red/white either to the 6,3mm terminal or better M6 screw !
Andy had it right !!

many thanks