Need help w my 2001 johnson ocean pro 115hp

[Lamont407]

I have a 2001 johnson ocean pro 115hp outboard motor. When I initially turn the key the bendix goes up an engages with the flywheel as it should. Then maybe 2 seconds later the flywheel no longer spins and only the starter spins. I've replaced the bendix and battery, what could be wrong?

 

[Crosbyman]

fwiw here is one answer from an intelligent source...

Q:
what would cause the bendix gear on a 2001 johnson ocean pro 115hp outboard motor to drop off after 2 seconds

On a 2001 Johnson Ocean Pro 115, if the Bendix gear comes up normally, cranks the engine for about 2 seconds, then suddenly drops off while you are still holding the key in START, I would look at a few things—but one is particularly common.

Most likely: the engine is briefly firing​

The Bendix is an inertia-drive. If the engine momentarily fires and accelerates even briefly, the flywheel can overrun the starter and force the Bendix back down. This is normal Bendix behavior. A very similar Ocean Pro case describes the Bendix dropping out just as the engine begins to fire.
So if yours does:
START → cranks strongly → ~2 sec → Bendix drops → starter spins freely
I'd first determine whether the engine is actually trying to fire at that instant.

But if it does it with NO ignition possible...​

This is important. If you disconnect the ignition so the engine cannot possibly fire, and it still drops out after exactly ~2 seconds, then I'd suspect:

1. Weak battery / excessive voltage drop
2. Poor battery-to-engine ground
3. Bad positive battery cable or connection
4. Starter drawing excessive current
5. Sticky/worn Bendix drive
6. Starter shaft/helix contaminated or damaged

There is a documented case on a Johnson where the Bendix dropped after about two seconds even with the plugs disconnected; the eventual investigation showed the problem occurred only when the starter was under the load of engine compression.
Also, a 1996 115 Ocean Pro had intermittent Bendix engagement caused by a sticky Bendix, which was freed up with lubrication.

A very useful test​

Since you work with scopes/meters, I'd do this:
Put a voltmeter directly across the starter motor terminals and watch it while cranking.

• Battery sitting: ~12.6 V
• Cranking: ideally well above 10 V
• If it plunges substantially lower just before the Bendix drops, investigate battery/cables/starter.

Then repeat with the spark plugs removed.
If it cranks continuously with the plugs out but drops out after 2 seconds with the plugs installed, that's a big clue toward starter torque/current/compression-related trouble, rather than the ignition switch.
And don't overlook the Bendix itself: it should move freely up and down its helical shaft. It should not be gummy or sticky.

 

[Chris1956]

The Bendix will kick out and not re-engage, when the motor fires. It is a common problem on all engines and can be solved by tune up or altering your starting procedure.

So, pump the primer up until hard. Hold the choke button and crank the motor until it starts. Is the Quick Start system working?

 

[dingbat]

Had the same issue with mine.
Slowly getting worst over time.
Changing a suspect battery cable which helped. Changing the starter resolved the issue.

 

[Chris1956]

That is not usually a starter issue. The bendix is designed to kick out when the engine fires. The engine is not supposed to fire only once, however.

 

[dingbat]

That is not usually a starter issue. The bendix is designed to kick out when the engine fires.

The bendix is driven by enertia.
What rpm is required to kick the bendix into position?
What is “cranking” rpm specification?

 

[flyingscott]

Check your bushings that the upper bendix rides in.

 

[Chris1956]

The bendix engages the ring gear when the starter starts to spin. Once the bendix gear is kicked out, the starter and gear must come to a complete stop, in order to engage the bendix gear again, when the starter starts to spin.

The rule of thumb for Starters is about 300RPM cranking speed of the motor.