Leaking lower unit oil

[Aruss1984]

2008 Optimax 1B544934

I've got lower unit oil leaking from the prop collar. I assume I've got a bad seal. Could it be the shift shaft seal or driveshaft seal? Any other possibilities?PXL_20250420_215222350.jpg

[Savage]

Could be prop shaft seals. Lower unit should be pressure tested. Remove the prop and inspect for fishing line.

[Aruss1984]

Will do. Thanks Savage.

Could be prop shaft seals. Lower unit should be pressure tested. Remove the prop and inspect for fishing line.

[Aruss1984]

Removed the prop. No sign of any line around the shaft. I don't see any oil coming from the seal but there is oil where my finger is pointing. I don't have a pressure gauge to test for leaks but am trying to source one. Any obvious signs of shaft seal failure?

Is it also possible it's 2 stroke oil from running rich idling on muffs? The bearing carrier has some on the top surface and looks to be pooled in the bottom of the housing

PXL_20250421_131855881.jpgPXL_20250421_131906043.jpgPXL_20250421_131914808.jpgPXL_20250421_145029200~2.jpg

[Savage]

Gear lube has a vary distinct smell. Has the gear oil been changed lately?

I would probably drop the lower unit next

[Aruss1984]

I changed the gear oil in the fall before winter. Haven't ran it with the new oil. Only ran the motor in my driveway to bleed oil lines. Noticed the black oil puddled under the LU a few hrs later.

Gear lube has a vary distinct smell. Has the gear oil been changed lately?

I would probably drop the lower unit next

[Savage]

I changed the gear oil in the fall before winter. Haven't ran it with the new oil. Only ran the motor in my driveway to bleed oil lines. Noticed the black oil puddled under the LU a few hrs later.

Perhaps you overfilled the lower unit. Follow this link for filling instructions >>>where is oil fill and drain plug on 250 Proxs
Does it smell like gear lube?

[Aruss1984]

I don't think it was overfilled. I capped it once it came out the overflow. I compared the smell of gear lube and the black oil and they smell different.

Perhaps you overfilled the lower unit. Follow this link for filling instructions >>>where is oil fill and drain plug on 250 Proxs
Does it smell like gear lube?

[JOE54]

thats a standard service master gearcase (capped at overflow ) is too full

[Aruss1984]

If overfilled, can I open top screw and allow excess to drain or do I need to drain completely and refill?

thats a standard service master gearcase (capped at overflow ) is too full

[EuropeanAM]

Opening the vent screw while engine is at level trim would be a great starting point to help determine if it's over-filled.

Curious question: Was this engine FOGGED before it was put up for the winter? If so... that may simply be fogging oil combined with some carbon.

[Aruss1984]

Yes, it was the first start after fogging. I think you may be correct that it was that combination that I was seeing. No excess oil when overflow opened.

Opening the vent screw while engine is at level trim would be a great starting point to help determine if it's over-filled.

Curious question: Was this engine FOGGED before it was put up for the winter? If so... that may simply be fogging oil combined with some carbon.

[JOE54]

good

[Aruss1984]

Update: motor ran well today for first outing of the season. No oil leaks or any other issues. No explosions or fires either so I feel it was a win haha.

Sidenote: the fishing on St Clair was terrible. So much wind the last few days turned it to chocolate milk