Starter won't engage but spins, Bosch, Normag

[jelo]

Starter won\'t engage but spins, Bosch, Normag

Hi all

I have a problem: The starter motor spins on my Normag-Zorge engine (2-stroke diesel) but it does not engage. It is a Bosch starter and when it is on the work bench it throws the cog whell and rotates merrily. But when mounted on the engine it still tries to throw the cog whell but the wheel never engages. Indstead it spins while pressing against the flywheel.

Could this be something with the "holding" circiut as opposed to the throw circuit? Your guess is as good as mine,

Best regards
Jeppe Locht

 

[Soundguy]

Re: Starter won\'t engage but spins, Bosch, Normag

Try cleaning the drive and shaft with brake cleaner or carb cleaner. Many tractor drives rely on fast spin up to throw out the drive gear, or suck the drive gear in ( as in a ford N ). Any grease or contaminants can cause drag and prevent the gear from engaging.

Also.. look fro wear ont he flywheel ring gear. is it possible that the teeth are slightly worn, or even ragged preventing gear mesh. Some peopl etake a large screw driver or tire iron and rotate the flywheel a few teeth to see if it is an engagement problem. Of course, if you see some rough teeth.. hit them very lightly with a flat file first.

Next.. check electrical connections at battery, and ground strap, terminal ends and solenoid or starter relay. dirty contaminated/painted or coroded terminals drop voltage, and that will cause starter problems. Some tractor have the ground braid attached right at a starter flange bolt.

Is there any play int he starter shaft.. like bad bearings or bushings that might be causing it to bind / drag?

hope this helps.

Soundguy

 

[jelo]

Re: Starter won\'t engage but spins, Bosch, Normag

Thanks for your suggestions.

The starter is the solenoid type (Bosch ejd 1,8/12 R42) so I suppose this means that it does not rely on fast spin-up? I mean the solenoid should be pushing the cog wheel, it should not just be moved by the spin-up?

The teeth of the fly wheel are both a bit worn looking and somewhat rusty on the surface. I have already once tried to turn the engine over a bit and there was no change (ie still no engagement by the starter). Maybe I should try a few more times and see if I get lucky.

There does not seem to be much play in the starter bearings. I will check more.

It is very hard to find a replacement starter and the service for this model has stopped a few decades ago... I really must fix this myself.

Also the engine is not running too well (2-stroke diesel) and until I get the starter to work I cannot concentrate on finding and fixing the engine problems /forums/images/graemlins/frown.gif

I am open for more suggestions. /forums/images/graemlins/wink.gif

Jeppe

 

[jelo]

Re: Starter won\'t engage but spins, Bosch, Normag

SOLVED!

It was the freewheeling gearing that did not engage when under power. The cog wheel was inserted properly into the flywheel but the axle rotated without pulling the cog wheel. A new gearing is in the post right now.

Thanks for the reply.

j.