nois in lower unit 1996 75 hp

[cbelk]

Hi guys my motor is a 96 75hp 3cyl two stroke merc. I changed the oil in the lower unit and ran it with muffs on so I could adjust the shift cable, while it was running I noticed I could here the gears working inside the casing there was no clunking or banging or even grinding but it did seem like it was loud. It may be I,ve just not noticed this before its a new motor to me. The prop has no more than 1/8th inch of travel maybe even less, and the gear oil is fine, should I be worried everything seems to run out fine Thanks

 

[galamb]

Re: nois in lower unit

Was the noise like a whine?

Was the noise present in forward, neutral and reverse or did you check?

In the gearcase you have a number of different bearings a couple thrust washers and possibly a few shims - any one of which can whine when it starts to go.

The gears in these, like most outboards built in the past 30 years or so have taper cut teeth (hypoid ground) so they don't really whine (too loud) on their own.

A bit of noise might be normal, but best to try and isolate it first. If it's only occuring in forward gear, for example, that's possibly an indication that there is the start of a problem...