Overview- Mariner 40M 6E9 / Yamaha 40 hp - Japanese Short Shaft Outboard Motor 

You should be ok, there’s no air filter anyway

@@MarineEngineServicing Thanks! Ours didn't have one & they are pretty pricey.

Depends where it’s leaking from ? Prop shaft seal, drive shaft or gear selector

@@MarineEngineServicing I do believe it’s from prop shaft seal and prop shaft seals as it’s leaking only where there exhaust comes out

I also forgot to mention that my engine is the 40ml 6e9

You will have to remove the bearing carrier which is held on with 2 bolts, this sits just behind the prop. Assuming the fluid leaking is gear box oil. Once off you can remove and replace the 2 lip seals around the prop shaft. Replace the o ring on the carrier at the same time. You will need a set of pullers to remove the carrier from the gearbox. This can be done without removing the lower unit from the engine

@@MarineEngineServicing thanks a lot for your help Sir, really appreciate it!! I also did a test to maybe understand better my issue. So I drained the gear box and cleaned the inside of exhaust where it was building up oil. Once I did cleaned it and put back oil to the gear box and it didn’t leak until I turned the propeller shaft. I don’t really understand much about outboards and lower ends and maybe you can help me identify where the oil is leaking from. Cheers chief 🙏🏽💪🏽

It should have some auto generated in RU-vid ?