I have a gen 4 and a gen 5 502.At the oil adapter,the line coming straight down,is that the supply out or return to the block?Is it the same on both gen 4 and 5?I need to plumb my coolers and filters this weekend and want to make sure I do it right.I hate rebuilding and blowing things up twice.Any diagrams would be greatly appreciated.

Thanks Nordic95

How about upgrading oil adapters?How restrictive are the stock units compared to the aftermarkets.I am running #10 line and AN fittings.I was just wondering who carries a good non restrictive adapter.I noticed the holes in the stock units are only about 3/8 of an inch.Don't seem good for 600HP,but then the cooler is the same way.

Nordic95

remember two things,

a) the flow is only going to be as restricted as the most resticted point

b) there are press releif valves in the adaptor set at 30 psi

I have read that the relief could be much less psi then 30#.Should I get adapters without releif valves?and lager ports for more flow?who carries a good one?

with out relief valves if somethings clogged(like filter) you can kiss your mtr good bye

I just noticed my gen 4 has both hoses out the sides,what one is the return to block?

Nordic95

Some good info here

http://www.offshoreonly.com/forums/s...=1#post1651729

and here

http://www.offshoreonly.com/forums/s...4&page=1&pp=20

All the Merc motors Ive worked on have been filter first, then cooler. Theres arguments to be made each way. I plug all my bypasses and use dual filters with their own bypasses.

Once you've got the lines run the way you think is right, unhook the return line to the engine, fill the engine with oil, stick the open line in a pan, PULL THE COIL TO DISTRIBUTOR LEAD SO IT WON'T START, and crank the engine over a few revs. The oil shud run out into the pan, confirming flow is correct. This prevents the brain clouds from forming and causing mistakes. We've all done it.