Kawasaki ultra 300x won't start

[steve45]

OK then, sitting for months without charging a battery will kill it. I guess it is 'a thing'. A brand new charged battery must be charged periodically or it will die. Dirty or loose battery cable connections will also give the same result.

Sitting for long periods can cause a Bendix to be sticky, but your 'Ski doesn't even have a Bendix. A Bendix is a helical screw-like shaft on which the pinion gear is mounted. When the starter motor starts to spin, inertia causes the gear to move out on the shaft and engage the flywheel. If the shaft/gear get rusty, the gear won't slide.

However, your 'Ski uses an over-run clutch. The gears are always in mesh. When the engine starts, the pinion spins so fast that the sprags inside the clutch disengage. If that gets rusty, it usually doesn't engage at all and the starter just spins without spinning the engine.

[Cranofwaterfell]

OK then, sitting for months without charging a battery will kill it. I guess it is 'a thing'. A brand new charged battery must be charged periodically or it will die. Dirty or loose battery cable connections will also give the same result.

Sitting for long periods can cause a Bendix to be sticky, but your 'Ski doesn't even have a Bendix. A Bendix is a helical screw-like shaft on which the pinion gear is mounted. When the starter motor starts to spin, inertia causes the gear to move out on the shaft and engage the flywheel. If the shaft/gear get rusty, the gear won't slide.

However, your 'Ski uses an over-run clutch. The gears are always in mesh. When the engine starts, the pinion spins so fast that the sprags inside the clutch disengage. If that gets rusty, it usually doesn't engage at all and the starter just spins without spinning the engine.

Steve,
I distinctly remember having the gear assembly (bendix) out and in my hand when I had the one ski completely tore down. I also remember thinking that maybe I should replace it, but after looking at the price tag and being advised that those things don't go bad, I declined. I also remember thinking that IF it needed to be changed it would be a real BIG deal to get at it later since it's buried inside the case by the generator. Anyway I didn't change it/not sure that's the problem anyway since both skis behaving exactly the same.

So how about a little dual on how exactly that thing works? I'm guessing the big gear end rides on the rotor (flywheel) all the time and the small end that starter goes into somehow turns the big end during starter engagement, then disengages when engine starts? I'd really like to know/think it would help me in diagnosing the issue.

Thanks in advance,

Cran

[steve45]

https://en.wikipedia.org/wiki/Sprag_clutch

[Cranofwaterfell]

^^^^^^^^^^^^^^^^^^^^
Thanks Steve that helps, but still can't quite "see it" in my mind. These pics are from link you sent me and both imply a change in direction to disengage the mechanism from the now running engine. I don't see a change in direction between the gear assembly/bendix on starter end and the spinning rotor/flywheel on the engine (after the engine fires off). Only difference I see is the rotor now spinning much faster than the starter, but in the same direction as when the starter engaged. The illustration of the freewheel/overrunning clutch makes the most sense in my brain, but still has arrows pointing in opposite directions, implying a reverse in direction disengages it. I *think* somehow it must disengage mechanically when the torque on the device suddenly is coming from the rotor on the engine vs from the starter motor (although without a change in rotational direction of either end of device). Is that about right?

[steve45]

Thank relative speed. Which one is going faster while cranking? Which one is going faster while running?

[Cranofwaterfell]

Yeah I think I see it now, and it IS kinda hard to put into words. I'm gonna call them inner/outer parts corresponding to starter side/rotor side. So initially the starter turns (inner) and grabs the outer part (rotor side) which causes the engine to turn over/start. At engine start the outer part rotates much faster than the inner, creating in effect a reversal of direction (relatively speaking), and a release of the grabbing effect of the now much slower inner part.

Pretty cool, thx for helping me "get it."

[Cranofwaterfell]

Problem went away after putting skis on battery tenders. No hesitation, cranks right over with one push of starter button. Definitely a battery issue (I think).