My new boat has a beefed up 502 efi, and the previous owner was running a Wix oil filter instead of the merc. Any reason for this, should i just go with the readily available merc?

The filter that is on it now is a Wix Racing p/n 51061R. I was at Farm and Fleet checking out the price of the Mobile 15W-50 and also saw that Mobil has a extended performance oil filter, P/n i saw was something like MI-301. Anyone run either of these or have any info on these filters........

I have a pair of '96 502 MPI's, and I run the Mobil 1 filters. There are 2 that will work, the M1-111 or the M1-302. The 302 is much bigger, but there is not enough room on mine to use them so I use the 111. They are great, and you will be amazed at how clean the oil stays. BTW, the 301 will NOT work (different threads).

Can these filters be mounted upside down? I thought the Merc. filters had a check valve in them that kept the oil from draining back since they are inverted.

how's the filter going to drain if it's upside down. It will always stay filled.

Gravity if there is no check valve. It will drain back through your lines/pump and into the pan.

The M1-302 has the advantage that it uses a synthetic filter element. It won't swell up like paper elements and cut off filteration if there is moisture in your oil.

I don't agree with this, if the pick-up for the oil filter was at the bottom, then i can see that. My opinion, unless someone has proven this happens. I'd like to prove it myself, but i need to run the motor before changing the oil to day, otherwise i'd unsrew the wix filter i have and see how much oil is in it, i'm pretty sure i've read on here that the wix racing doesn't have a check valve either.