Petroleum Sheen Coming From Exhaust After Shutdown

[CaspersCruiser]

I'm still getting to know my 2012 R27 and its Yanmar. Yesterday afternoon/evening I ran it fairly hard as a performance test, 3,000 rpm for a couple hours- 1.1 hours upstream to an anchorage and .9 on the way back. When I arrived at the anchorage, I noticed a small sheen on the water behind the boat after shutdown and setting the hook. When I arrived back at my slip after the trip, I was quite disturbed by the size of the apparent petroleum sheen forming on the water's surface behind my boat. It appeared that it was coming from the exhaust port. I went back to the slip this evening and the sheen had dispersed. Any ideas what's going on here?

 

[Don and Brenda]

Had the same issue, quite a few people looked at it before finally found the problem, it was the transmission oil cooler. Finally figured it out after running for many hours and came into the dock and transmission would not change gears. Temp fix was add transmission fluid. Hope it is something causing your issue as very expensive to fix.

 

[Andrew Custis]

I would also make sure this isn't from your trim tabs. I have seen the cylinders leak over time and they can create a sheen behind the boat. I would check the fluid in your pump and verify that it is to the full mark. Check with the tabs in the up position.

Don and Brenda made a note of their issue but haven't heard of many others. Certainly something you might want to get a Yanmar dealer involved with to inspect.

 

[CaspersCruiser]

Thanks for the input. To my great relief, I have determined it is the port side trim tab that is leaking. Now the question is what's involved in fixing it?

 

[knotflying]

Call Bennett or look at their site on line. They have several videos on repairs. Probably a replacement piston and you will be up and running.