ELPTO 125 Lower Unit "Clunking" in reverse

[thomasfouraker]

Serial number in signature for the 125.

Just noticed in while in reverse, the lower unit makes an intermittent "clunk".

I put a stethoscope and confirmed it to be the lower unit. Only occurs in reverse. Forward gear is quiet.

I disconnected the shift cable to rule out improper adjustment and shifted it firmly into reverse by hand with the same result.

This isn't the typical clutch dog "grinding" that is consistent with improper engagement, it is a clunk clunk clunk noise.

Next logical steps seems to try to see if it still makes the noise with the prop removed, and drain/inspect the fluid if so. Other than that is seems the LU will need to be repaired.

[EuropeanAM]

Is this while IN the water, with the prop installed (or while on a flush attachment, with no load)?

[thomasfouraker]

No noise with prop removed.

Could this be the aluminum prop and hub making the noise?

Forgive my ignorance in regards to this motor, its new to me and I am learning it.

[thomasfouraker]

Sorry Don, we posted almost at the same time.

This is OUT of the water on muffs, no load at idle.

[EuropeanAM]

You may simply be hearing the clutch rattle that is inherent to these when not loaded.

Place it in the water, put it in reverse, and listen for any pronounced "knocking".

[thomasfouraker]

Yes sir, will do.

Lastly, is it ok to run the High Performance Gear Lube in this particular lower unit?

I noticed it has the traditional Mercury Lower unit fluid and when I go to change I would prefer to use the High Performance just to make it easier and more convenient as that is what I run in my larger Optimax.

Thank you very much for all your time and effort. Good to see you posting more often, you had me scared there for a little bit. Hope all is well.

[EuropeanAM]

High Perf is an Excellent choice.