Checked the oil in my seawater pump today, pulled the plug and thin gas dilutted oil came out. I just put a new fuel pump on this last year, with new oil. Is it normal for this to only last a season and have to change that oil again cuz of fuel dillution?

Have seen this with the stock Merc pumps. I would say, as long as the fuel isn't coming out of the vent line, you should be ok.

On my 525SC, I used to change the fuel pump/sea pump lube every time I changed the blower lube, which was about every 30 hrs. It was always somewhat fuel diluted. Never had any issues with the fuel pump other than that.

Pretty sure Gear lube is the reccomendation.

That's what i'm using, but even with a new fuel pump, it get's dilluted with gas. Seams to me these merc fuel pumps are junk. What is failing in them that it let's gas through to the cam arm?