I just picked up an old Zephyr 20 inch cylinder mower. Upon running the engine, the cutter and roller are both permanently engaged.

There's what appears to be a cone type clutch enter image description here and I have read it also has a dog clutch although I can't see evidence of it. Pulling the clutch cable pulls the bottom of the left hand lever (in the image) to the right but doesn't appear to do anything to the clutch, other than bend the plate on which its fulcrum is mounted to the left, away from the clutch.

I've tried slackening the cable and the clutch doesn't disengage, and I've tried pulling the cable really tight.

Working hypotheses is that a) the friction faces have mated together, or b) I don't understand what's going on.

What visible indication should the clutch in the picture give, that it is being disengaged? Should e.g. the black sleeve slide over the spindle? Should the narrower part of the cone move inside the wider part or are those fixed together?

What's standard practice from here to diagnose and fix it?

If I were to separate the clutch from the machine and attempt to compress it in a vice, where would I apply the pressure for least risk of causing damage?

Also, does compressing the clutch engage or disengage it?

As it happens there are some better pictures of the same clutch here, although it's called a "weighted driveshaft" there.

  • 1
    Welcome to Motor Vehicle Maintenance & Repair! Apr 1, 2021 at 14:12

1 Answer 1


That black tube doesn’t look original to me. I think you are missing the dog clutch -

enter image description here

This photo was taken from some of the other parts that the same eBay seller is selling.

It looks like it is supposed to go on the splined shaft of the weighted driveshaft -

enter image description here

You may want to ask the guys on this website for help.

  • Turns out I too found that listing since posting, and identified the dog clutch. It's outside the left of the picture on the other side of the side plate. Just the cone clutch I can't work out how to free up. Apr 1, 2021 at 14:00
  • I think your best bet would be to disassemble it. It doesn’t look too difficult.
    – HandyHowie
    Apr 1, 2021 at 18:47
  • Disassembly isn't the hard part 😁 I'm thinking squeeze it in the vice first, see if that separates the plates. Apr 2, 2021 at 7:43

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .