Cranking speed?

[andyzeetec]

Does anyone know the cranking speed for these engines, I read somewhere normally 200rpm, not sure though.

I suspect starter motor is at fault, battery is fine, just need to confirm before shelling out

Thanks

[Pete126]

Never seen a spec for that If its cranking slowly have you checked the cable from the battery to the starter for damage or water ingress.

[Rusty's Uncle]

Like Pete says I would check all terminals / connections at battery , earth straps front & rear and starter. Then if the battery is fine and the starter sluggish I would try a new set of brushes in the starter motor. It is amazing what a good internal clean up and new brushes can do sometimes, that is assuming the starter bearings are ok 

[andyzeetec]

Thanks Guys.

I've checked connections, earths.

I read about cranking speed here... http://northatlan.com/Starterdrives.htm

This is quite an interesting in depth clip on starter operation.. https://www.youtube.com/watch?v=8WD5Q_PF3pM

Just found a helpful bit in the club member section workshop manual which covers Fault diagnosis/bench testing, so will have to whip it off at the weekend. Hopefully it's a case cleaning the commutator blades/slots and new brushes. Any idea on how to source the brushes, part no ?

thanks for help.

[andyzeetec]

Run starter motor up on the bench and the armature has quite a bit of axial movement so I reckon its shorting out on the field. Commutator looks good and brushes are not bad. Ordered the bush bearings from 126fan (great service from those guys). They arrived today with brushes, 9 quid delivered, but havent had a chance to fit yet. Fingers crossed.

Bushes item 2 on pic

[andyzeetec]

Just an update,starter all back together with new bushes & brushes.   Blimmey does it make a difference, the engine doesnt know whats hit it, cranks over so much faster . It's improved starting no end.

So if your engine is cranking over slowly and ruled out timing, battery,connections etc, check out the starter motors armature isnt shorting out to the magnet due to worn bushes/bearings.