Boating How-To’s - Intake Manifold Pictures - productive comments?

So I removed the intake manifold to replace the VST filter and saw an inside of an intake manifold for the first time.

So, I don't really know how to interpret it like sparkplugs, because spark plugs have guides and pictures. The pictures are ordered from the top to the bottom. It's an 02 Yamaha F115.

There was sitting oil in the motor part on #1, and then some in #2 and less in #3.

I tilted the motor into the vertical position and checked the oil and the dipstick was full of oil, I assume the guy put in too much oil with the oil change before delivering this motor to me. I can fix that. Hopefully the sitting oil is a direct result of the excess in the system. I'll check the plugs soon.

Any comments on the buildup? I thought the intake manifolds are supposed to be clean, or at least evenly dirty. If someone can help or explain to me how this stuff gets the way it is it would really be helpful! Thanks in advance!

Remember that PCV hose you took off, from the valve cover? That's pulling the hot gasses from inside your engine, and feeding them through your intake, and into the combustion chambers. All you are seeing is some of that stuff that builds up over time on the casting. Really not a big issue. It would be nice if there was none, but it's not gonna happen.

Remember that PCV hose you took off, from the valve cover? That's pulling the hot gasses from inside your engine, and feeding them through your intake, and into the combustion chambers. All you are seeing is some of that stuff that builds up over time on the casting. Really not a big issue. It would be nice if there was none, but it's not gonna happen.


So I guess that's why people install "oil catch cans" on street applications. I cam sure I can design on had I the time. Maybe one day.

Genius! ...and knowing is half the battle. Thanks a bunch!