I am the original owner of a 2007 200hp optimax. Low hours. I did a search and found some hits on optimax oil leaks but none explain my situation. One day last fall I noticed there was some oil on the transom which appeared to be leaking from the cowling of the motor. I looked and looked and couldn't find any leaks around the oil pump or lines. I finally found the oil was seeping through the very bottom of the aluminum intake plenum where it bolts to the intake manifold. With further inspection I found there was a small pool of oil sitting in the bottom there which is seeping through the mating surfaces of the plenum and intake manifold. I'm not 100% sure but I don't think there's a gasket here as it's machined surfaces making contact but regardless, oil is able to seep through. More importantly, where is the oil coming from? To me it looks to be leaking from inside the engine somewhere and running back up through the reed valves and into the intake plenum. There's no where else for it to leak down into the engine from the outside. Am I right with this conclusion?
Also, I originally thought the issue was due to leaving the engine tilted up on the transom mount too long but it appears to still collect oil in that spot even when put almost all the way down. It didn't do this when brand new so something has changed. within the last year that's causing this. From my inspection and diagnosis I gather the oil is leaking out of the oil injection lines and running backwards until it ends up in the bottom of the intake. Is this a sign that something isn't holding seal anymore and letting oil randomly run out (oil pump or something else)? I have no alarms or other issues and the engine runs great. I did clean up the pool of oil by removing the throttle valve assembly. I have attached some pictures of my problem.
Also, I originally thought the issue was due to leaving the engine tilted up on the transom mount too long but it appears to still collect oil in that spot even when put almost all the way down. It didn't do this when brand new so something has changed. within the last year that's causing this. From my inspection and diagnosis I gather the oil is leaking out of the oil injection lines and running backwards until it ends up in the bottom of the intake. Is this a sign that something isn't holding seal anymore and letting oil randomly run out (oil pump or something else)? I have no alarms or other issues and the engine runs great. I did clean up the pool of oil by removing the throttle valve assembly. I have attached some pictures of my problem.
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