Starter motor not engaging

·         Max Saunders

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Hi Doug

Over the last few weeks my 2200 engine s/n 22A 3553 , 179 hours, has shown a tendency not to engage the ring gear. It might take 2 or 3 attempts to get it to engage.
If it fails to engage, the motor revs up to a very high speed. Presumably the bendix gear is not engaging the ring gear.
The battery is new.

The overhaul manual (para 5.13.3.3) says to lubricate the bushes when doing an overhaul.

Should the bendix assembly be lubricated as well? If so, what with?

Or should I just clean it to make sure there is no grease or anything else on the bendix assembly?

Thanks for your advice

Max

J160 ZK-CLX, 720 hours.

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·         Doug Smith

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Hi Max,
First thing to check is the condition of the ring gear, see if there are any teeth missing.

Next from there would be the bendix. Check for damage to the teeth on that. Have a look and lubricate it if it's dry or clean off the old grease/apply fresh if there's an excess. Any good grease should do the trick, but if it's been running dry you might also want to apply something a bit thinner too. There are a couple of bushes in the bendix housing that would bear checking too, make sure they're serviceable.

Regards,
Doug.

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·         Max Saunders

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Thanks Doug. I will pull the starter and let you know what I find.

Cheers

Max

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·         Jeff Shultz

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I had the same symptoms you describe, and pulled the starter motor a total of 4 times attempting to clean and re-lube it. It turns out that the clutch was going bad, despite appearing to work fine when disassembled on the workbench. Replacing the clutch solved all problems. The clutch is a standard automotive part, mated to the starter motor with a custom clutch housing made by Jabiru. I purchased the replacement clutch thru Jabiru USA for about $175 US.

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·         Max Saunders

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Starter removed and inspected. All gear teeth OK.
Small amount of grease on inner bush clutch gear and clutch shaft.
Absolutely no sign of grease on outer bush and corresponding end of the clutch shaft. Traces of bush material found on engine in vicinity of right coil where thrown by the rotating ring gear.

Inner bush id: 11.07 mm radial to ring gear.
11.03 mm tangential to ring gear
Clutch shaft at inner bush od: 10.96 mm

Outer bush id: 12.04 mm radial to ring gear
12.23 mm tangential to ring gear
Clutch shaft at outer bush od: 11.98 mm

The thrust bearing (I presume that's what it is) between the clutch mechanism and the outer bush was completely dry, hard to turn and frequently grabbed when turned.

All gears and bushes were cleaned and lubricated with grease.

The thrust bush was lubricated with a few drops of oil, after which it turned freely without grabbing.

Starter refitted and - so far with 4 cycles - has operated correctly.

Max

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·         Max Saunders

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You are right, Jeff, it was the bendix clutch.

The fault came back not long after I reinstalled the motor after cleaning it.
I replaced the bendix clutch assembly with a new unit CPM 6352N from Jabiru in Bundaberg about 4 months ago and the starter has been working fine since.

Max ZK-CLX J160

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