Testing Starter Motor

[emmo1210]

Hi Guys,

Was having some starter problems (1990 90 rude), turned out brushes were done.

Replaced motor cap, new brushes etc.

When bench testing the starter now, with positive to motor post and negative to motor case motor turns over fine but Bendix gear just shoots up spiral shaft and straight down again, it doesn't stay up, motor just continues to turn. it would not stay our for long enough to turn flywheel over.

Does anyone have any idea what problem could be?

Thanks
Emmett

 

[ohioriverat]

Re: Testing Starter Motor

I believe what kicks it up keeps it engaged when mounted on the engine,the splined shaft the gear slides up i believe it's called a wishbone on a recoil starter. have you tried it on the engine?

 

[boobie]

Re: Testing Starter Motor

If it spins over good try it on the mtr once and see what happens.

 

[Fed]

Re: Testing Starter Motor

Once the starter is up to speed there's no more acceleration to keep the bendix up.

 

[emmo1210]

Re: Testing Starter Motor

Thanks all for replies.

Had mounted on mtoor and would only spin up, turn flywheel few times and drop out again.

Am going to try charging battery up full tomorrow and try again (although thought battery was ok)

Will post my result.

Thanks
Emmett

 

[emmo1210]

Re: Testing Starter Motor

Ok so remounted motor with newly charged battery. Motor had no problem turning over flywheel but as soon as one cylinder fired it shot starter bendix down (as stated above) and engine quit.

Tested for spark and seem to be missing spark on no2 so have a new coil on order.

Would the loss of one spark prevent it from starting on a V4?

Seems to be getting sufficient fuel as when cranked over with plugs out could see fuel mist exiting.

Regards
Emmett

 

[Joeshow]

Re: Testing Starter Motor

hmm i'm having the same problem with my starter... its old, thinking it needs a rebuild... looking forward to see how ya make out! good luck!

 

[dstom]

Re: Testing Starter Motor

Last spring, I rebuilt the starter on my '72 100hp 'rude, so here are my thoughts. Please note, I am not a mechanic by any means.

I think I would clean the bendix shaft thoroughly, and then relube the shaft, but with only 50% of the lube used originally. I believe the gear is spun up by centrifugal force, which is caused by inertia. When both the shaft and gear are spinning at the same speed, gravity will pull the gear downward.

I hope this helps!

 

[boobie]

Re: Testing Starter Motor

If your mtr isn't running correctly and miss firing on start up it could " fool" the bendix to kick out. Disable the ignition, crank it over and see what happens. If it stays engaged you have mtr probs.

 

[emmo1210]

Re: Testing Starter Motor

Hi,

I replaced the faulty coil and can now start up alright, thanks all

 

[Silvertip]

Re: Testing Starter Motor

The bendix on an inertia starter are siimple physics. The bendix is normally at rest. You hit the key and the immediate spin of the starter against the at rest bendix causes a screw like effect thus causing the bendix to rise to mesh with the flywheel.. When the flywheel begins to "drive" the "bendix" (as in goes faster) rather than the bendix driving the flywheel, the bendix will drop down. An engine that pops briefly during startup will cause what you are experiencing and is perfectly normal. You need to tune the engine so it starts.