Featherweight Gearbox Oil Capacity?

[Chrisc161076]

Anyone know the approx. capacity the gearbox of a featherweight takes to fill it up correctly? Thanks

[livewire]

I just pour some in, then stand the engine vertical to allow the access to drain and screw the filler plug back in. Jobs a good'un

[Chrisc161076]

I thought of doing that but thought if it was a known quantity perhaps it would be quicker and less messy, just measure fill and confirm.

[Oyster 49]

The featherweight capacity is "Not a lot" so previous advice is about right! If there is a bit of overflow from the filler then it is about right. Change it a few times each year and leave it full of fresh oil over the winter.

[phil]

IIRC it's 125ml for the featherweight 2.1:1 box, 250ml for the 3.5:1 box 40+ and Century, and 500ml for the 4:1 gearbox on the Silver Century.

[Gannet]

is there any technical disadvantage (apart from possibly using more oil - taken over a running period) in just filling it right up when the unit is on ground resting on the tank and prop?
Jeremy

[david doyle]

Because I cannot buy SAE 120 locally I value it very highly. I made up 250 ml vacum seal packs of it. drain the old. snip a corner on the pack and there is no waste. Also works well for small amounts of mix oil. Takes up less space in the boat's tool box. Of course I am a vacum sealing junky so to each thier own.

[Niander101]

is there any technical disadvantage (apart from possibly using more oil - taken over a running period) in just filling it right up when the unit is on ground resting on the tank and prop?
Jeremy

Yes you want some air in there
and it will sap power also
so pointless to fill it right up

[Gannet]

Thanks Niander for your comments.

Yes, filling it right up would result in a lot of oil churning. I have no idea how much power would be lost - would it be 5%?
Technically I don't know why one would want 'air in there'.

I am sure I am over reacting to seeing a few of the small 10:21 boxes completely dry of oil, resulting in wrecked gears. Also never quite knowing how much (of the small capacity) has leaked out; and worrying how much is left.
Even if I put new 'seals' on the prop shaft, I worry about how much water gets in and emulsion gets out past the pinion gear.
Jeremy