Oil leak from carberator?

[seesaintleo]

What can cause oil to leak from the carbs on a 40 hp 1989.

[boscoe99]

What is the model of the motor?

Premix or oil injected?

How much oil are you seeing?

[throrope]

Vintage sounds like the typical bullet proof 2-stroke. If you use the engine mounted 2-stroke oil tank I suggest resolving the issue before your next trip since that $2 of oil lubes an engine that requires six grand to replace.

If a 2-stroke, the oil injector lines have check valves. Some posts here talk about failure can let the oil pass into the carbs when not in use creating the appearance of a leak.

An often issue with the oil tanks is the level sensing unit. The seal on the $180 assembly over years can shrink or other letting oil pass when the level is above the seal, when tilted up, or with expansion of air in the tank due to temperature changes and create the appearance of a leak. The seal is on the "shaft" of the sensor and not at the cap. I stopped our leak by wrapping the seal with petroleum resistant thread tape similar to the white stuff used on gas pipe, but mine was yellow. I answered a similar question a while back with pictures on Post#4(?) of a different thread found by a search.

The other nuisance I've encountered is the rubber cap on the tank. That can work loose and pass oil.

Good luck and keep us posted.