Why fill gear case from bottom

[zboss]

Folks,

Why do you need to fill the gear case oil from the bottom hole (yamaha)? It makes an awful mess and you end up leaking out some of the oil....

- z

[leftbrainstuff]

Yamaha 2 stroke outboard I assume.

To purge the air. The holes are so small you cant fill from the top fast enough and cold gear oil is very viscous.

I use a 1 quart plastic bottle with a pvc tube and tapered plug. Works a treat. No mess no fuss. Having the oil nice and warm helps too.

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[zboss]

Originally Posted by leftbrainstuff

Yamaha 2 stroke outboard I assume.

To purge the air. The holes are so small you cant fill from the top fast enough and cold gear oil is very viscous.

I use a 1 quart plastic bottle with a pvc tube and tapered plug. Works a treat. No mess no fuss. Having the oil nice and warm helps too.

Sent from my SM-N900T using Cruisers Sailing Forum mobile app

Yes, we use the recommended yamaha pump assembly but you still need to take the pump out and put in the plug, during which some oil leaks out.

[capt jgw]

The oil is so thick it will trap air in the case and not be full. You fill from the bottom til it squirts ou the top. If you put the top plug back in before pulling the pump off, that will airlock the case and very little will come out the bottom hole. Or you can turn the motor on its side or almost upside-down before disconnecting. That might not be good for a 4 stroke, but a 2 stroke won't care.

[rwidman]

Originally Posted by capt jgw

............. If you put the top plug back in before pulling the pump off, that will airlock the case and very little will come out the bottom hole. Or you can turn the motor on its side or almost upside-down before disconnecting.

Of course.

[a64pilot]

Originally Posted by zboss

Yes, we use the recommended yamaha pump assembly but you still need to take the pump out and put in the plug, during which some oil leaks out.

After your sure it's full, put the plug in the top BEFORE you remove the hose from the bottom, you'' be surprised at how little leaks out that way.


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[zboss]

Originally Posted by a64pilot

After your sure it's full, put the plug in the top BEFORE you remove the hose from the bottom, you'' be surprised at how little leaks out that way.


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Yes, that is what we do.