[email protected]
New member
I have a 2000 40 hp Mercury outboard 3 cyl 4 stroke. I use the boat 3 or 4 times a year. Within the last year I have noticed the the crankcase oil level has increased. At first I thought it might be water but a leak down test , compression tests, lower and upper engine seals etc....showed no water. I changed the oil and then noted the smell of gasoline in the oil. A mechanic suggested that the fuel pump diaphragm might be leaking into the crankcase. I have a fuel pump that runs mechanically off a lobe or rocker arm in the engine. I have the engine manual and it shows two diaphragms. One of the diaphragms looks like a flat rubber gasket and the other is attached to what looks like a metal plunger with rubber membrane attached to this. I pulled the fuel pump off the engine and I don't see any obvious holes in the rubber/metal plunger. This part runs about 60 dollars. Has anyone had this problem or does anyone have any advise. Thanks for the help.
Greg
Greg