When the hell did they start mounting the oil filters upside down? What bean counter idiot came up with that idea? Ive never had a merc engine with the filter upside down. The HP's had them sideways on the flywheel cover which I also thought was stupid.

formula31...I would think the engineers designed it that way. Us bean counters have nothing to do with design :D

My old boat (454) had the same thing...never understood why!

I have that same upside down filter on my 454 MAG MPI and I thought the same thing. "Boy this is dumb" I think I used about a half a roll of paper towels the last time I changed my oil...

Where do you get those brackets to mount the filter the other, or should I say "right way"?

Trying to keep your boat clean while changing the oil is the worst. Here are some things I have found. If the filter hangs below the mounting plate, use the zip lock bag. It works great. If the filter sits on top of the housing, one of the guy's on the board suggested putting a hole in the bottom of the filter (remember is upside down). This brakes the suction in the filter and will allow most of the oil to drain out into the oil pan.

I don't know if it works yet. But it was suggested by someone on the board. I've got a couple of 500 HP's coming that have the filters mounted this way, and I think its my best shot.

By the way, I think they put the filters on upside down because they do not want you pre-filling it with oil. That would allow unfiltered oil into the engine and they want to avoid that. I have heard some suggest it is for space reasons, but I think its contamination.

So they don't want you to pre-fill the filter with brand new clean out of the bottle un-filtered oil to go to the engine?? But what do you do when you add oil to the engine?

When you add oil to the enging it goes directly into the oil pan via the drain's built into the head. Before that oil does any lubricating, it goes through the filter.

I don't think its as much a case of the new oil being dirty, as it is the individual getting dirt into the filter while its being filled. We started mounting our filters "upside down" for this very reason. We recommend a pre-lube system if your worried about dry starts.

Its an interesting discussion as these same filters are equipped with pressure bypass valves that will allow dirty oil to circulate through the engine if the filter should become clogged.

I do no like the "upside down" filters as I like to pre-fill.