Thread: RV8 Starter Motor

Most likely brushes will be worn down
Your local auto elec can sort it for you.

They are a very simple motor so if the windings are still ok and haven’t open circuited then new brushes should cure it. It’s just a series motor so as the name suggests everything is in series - winding, brush, rotor, other brush, other winding. If one part opens the motor stops. A good R&R with a clean l parts and some new brushes should get it going again. Measure the windings with a multi meter to see if they are ok before going to a whole heap trouble.

Thanks guys - hopefully it will be something simples.

If not it might be time to get a 12v starter and connect it up to the aux battery. However, I do need to get a new aux batteruy and was going to go full deepcycle AGM but if it has to start the engine I will have to rethink that and go with a combined starter/deep cycle battery as a compromise.

Garry

Finding parts such as brushes may be the biggest problem. Pre grey hair since I worked on these, but I think that the brushes are the same in 24 volt and 12 volt. Check the condition of the main contact inside the solenoid. Again cannot recall exactly, but most of the older ones it was possible to remove the moving contact and just reverse it so that the "good" side is now being used. The fixed contacts also wear and not make good contact.
The bushes are replaceable, but again may be hard to find.

Difficult to measure the resistance of the windings as it is so low. More important to make sure that they are not grounded.

If you end up taking it to a shop need to find a grizzly old white haired grumpy auto electrician to look at it, as the new breed of "technicians" are more just complete unit replacers!

Thanks for those comments - the solenoid is OK and I have a couple of 'new old stock' ones in my parts box. I also suspect the 12v brushes are the same as the 24v ones. I have an old 12v starter that i used for "body" parts so i will check the condition of its brushes and bearings etc.

Garry

Pulled apart the 24v starter apart and it is not good - structural failures inside.

This is the undamaged brush holder out of the 12v starter.
IMG_20190629_151007.jpg


This is the damaged brush holder out of the 24v starter with the broken bits on the table at the bottom.
IMG_20190629_150241.jpg

These pics are of the damaged armature.
IMG_20190629_151733.jpgIMG_20190629_150354.jpg


Well what happened first - good question. I suspect one of the brushes has welded itself to the top of the armature and then when power has been applied it has ripped the wiring out at the top of the armature and ripped the other brushes out, and broke the housing that holds the brushes.

While I have found a few sellers overseas that sell the starters, only one actually has them in stock and it is in the order of $600 plus shipping.

I will check with AJ on Monday to see if he has one and check with motor winders on redoing the armature - the end cap from the 12v starter with the good brush holder could go on the 24v starter.

Hmm, well the armature is definitely cactus! Unless you have done it dismantling it I rather think that it has been what is called "poling". The armature core is very shiny for one thing, and then there is some bright marks on the commutator risers. That is usually the result of worn bush bearings allowing the armature to contact either the brush holders, or the pole pieces.

Unusual type of commutator, usually referred to as a "sunflower comm". Good luck!

We use to run early vw and some 6 volt tractors with 12v starter, made for a healthy crank spin,don't know how they lasted but neverseamed a problem
cheers
blaze