Electric lawnmower sparks and stop after few second. Motor issue

[Jonny Vee]

Not sure this is right place to ask question.

I was given from my neighbour a Bosch rotak 36 which has stopped working. Plugged machine and sparks very bad for few second and then I guess thermal goes in and stops working.

I cleaned up commutator making looking like new. Replaced brushes with shining brand new and problem does not go away.

Before putting everything into the bin I would like to know what can be the issue as motor seems very simple

 

[Burnerman]

There's a very good chance that the insulation on the commutator windings has called it a day......the main signs are heavy sparking, a burning smell (even smoke) or the motor doesn't reach full operating speed. Often the tone of the motor changes too - a sort of growling sound.
Not worth the time and money I'm afraid!
John

 

[bernardgreen]

When cleaning the commutator it is essential to make sure there is no conductive material left in the gaps between the segments.

 

[Jonny Vee]

When cleaning the commutator it is essential to make sure there is no conductive material left in the gaps between the segments.


View attachment 265549

I knew that and carefully cleaned up every single one but no luck.

 

[Jonny Vee]

There's a very good chance that the insulation on the commutator windings has called it a day......the main signs are heavy sparking, a burning smell (even smoke) or the motor doesn't reach full operating speed. Often the tone of the motor changes too - a sort of growling sound.
Not worth the time and money I'm afraid!
John

This is exactly what that motor does. I think next step for the mower will be on the bin. it`s a shame I think they only used few time. Look new but Bosch may have gone very cheap on that

 

[Burnerman]

It's important to keep any air intakes clear so the motor can cool......no one ever does though!
John