How can I check gearbox.

[merc850xs]

Hi all.

Just picked up a Merc 850 XS, approx '76-78 as far as I can make out. The motor is running and pumps water but has no prop. The gearbox lever seems to shift ok. When lever is at one end the prop shaft will not turn in either direction. When centered there is a neutral, prop shaft turns both directions freely. Lever other end, prop shaft will not turn one way, but will turn in other direction and kind of clunks/ratchets when it turns.
Above test without motor running.

Does this sound normal? What checks can I do? Running test?

Hope to get a prop soon.

Any help much apreciated.

Dave

 

[j442w30]

Re: How can I check gearbox.

That sounds about right. It should ratchet in forward, spin freely in neutral, and not turn at all in reverse. If the engine is new to you I would change the lower unit oil and check the impeller if you have not done so already, and then work on finding a propeller. There is a separate propeller forum below that could possibly help you find a propeller to start out with, but they're going to need some info about your boat.

 

[Scaaty]

Re: How can I check gearbox.

850 XS is a SUPER classic (any XS merc is)​

 

[merc850xs]

Re: How can I check gearbox.

Good to know.

Have my eye on a prop. What type/grade oil is used in lower unit. Thanks again.


Dave

 

[j442w30]

Re: How can I check gearbox.

I think most gear lubes are 75w-90 weight but most places sell stuff specifically called "lower unit gear lube" which has additives in it to handle some water intrusion. I use Quiksilver High Performance Gear Lube, works great!