I know that this has been posted before but cannot find it. I have a 2005 F115 Yamaha and was checking the oil today and the oil was all the way up to the top of the dip stick.( Maybe an inch below it) I ran the engine about 10 min. and rechecked it later and it was a little lower. Any suggestions???
Seems the main causes are…
motor is not getting hot enough- may need thermostats
carboned up- Sea Foam
over propped
I had a very small amount of gas in mine after 100 hours, mechanic said run sea foam, and quit driving it like a baby. He suggested to hold it WOT for about 10 min a trip.
smell it
does it smell like fuel, and is it thinner than normal
fuel pump will also leak into crankcase
Called Marshall’s Marine and he suggested changing the t-stat. I dont have a noticeable gas smell but will change the oil after changing the T-stat. I did run the motor at idle last year during shrimping season for hours at a time, maybe that had an effect on the temp not getting hot enough.
186CC Key West 115 Yamaha