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Starter Bendix bounces up& down while cranking.

fbriggs

Member
Have a 1996 mercury Tracker that while cranking Bendix bounces up and down. Won't stay fully engaged.
96, 25EL, 0G309267, 2 new starters, new solenoid, new battery, 12.4 battery volts, 10.5 cranking volts. Any ideas some say nature of the beast. Has full engagement of teeth.
 
Looks like you covered all the bases except for connections. Starter RPMS are what drives the Bendix up the shaft and engagement with the flywheel. Loss of drive current to the starter allows the spring associated with the Bendix to return the Bendix to its rest position. Obviously drive current is driven by voltage across the starter and 10v is my baseline voltage to activate a starter and you said you are there....what you didn't mention is what I say below.

For starters, I'd get a voltmeter and connect it to the starter input power stud....the brass center part of the stud. Obviously get a good ground for your meter......the black battery wire (connector) connection to the engine block is a good place...nice and shiny.

Activate the starter and watch the voltage. If it is constant-steady when the problem occurs, input power should be ok. Next find a shiny part of the starter cased....if you can't find one, get some sandpaper and scratch off some paint till you see shiny metal. Put the voltmeter on this shiny spot and exercise the starter again. Does the voltmeter register 0 volts when the starter is spinning and the problem occurs. If it jumps around, your starter ground is not adequately connected to the battery return.

I have had boats since I was a teenager back in the 1955 period. I NEVER saw a "properly working" starting effort have the Bendix bounce up and down!
 
Thanks for the reply and info. I also have had motors since the 60s. Never thought about hooking the negative on bolt meter to actual starter. Have had it on the block and the battery when I did all the above test.
The other thing about this starter is I feel there is too much play between Bendix gear and ringear. But both are brand new. Just doesn't feel or look like gears mesh like they should.
Thanks again for your input.
 
Well the Bendix gear is designed to "force" its way into the ring gear. Sooooo a good part of the top of that gear is beveled to aid in the engagement....yes it doesn't leave a lot of contact area but it has done its job over the decades on millions of engines of all types.
 
Well the Bendix gear is designed to "force" its way into the ring gear. Sooooo a good part of the top of that gear is beveled to aid in the engagement....yes it doesn't leave a lot of contact area but it has done its job over the decades on millions of engines of all types.
Thanks just doesn't sound like any other motor I have worked on in past, that's all.
 
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