Guys a simple question. I want to install the oil drain system that Mercruiser sells to get the oil pan as empty as possible. I have been using the thru the dipstick pump out system for years but I don’t think I am getting all of the old oil out. It seems like a quick & easy method of changing oil by installing the drain plug system with the hose that you run thru your transom bildge drain hole & get all of the old oil out.
My question is what is the thread size of a stock HP500 oil drain ? I see these & don’t know which one I need :
Mercruiser Oil Drain Kit 3/8 in.-18 Threads into the bottom of oil pan
Oil drain kit Mercruiser 1996-2009 V-8 with 12mm oil drain thread Part # 32-805505a2

Thanks for the help!

It's 12 mm, i use eddie marines.you can but 2 of their kits to one of merc's

http://eddiemarine.com/store/cart.ph...l&p=11992&c=49

Mrfixxall thank you. I found this & it looks like the best buy I could find. Check it out.

http://bpi.ebasicpower.com/pc/MPI308-0380/MER14H-IB

For what it's worth I did the same thing on a couple of HP500's. One while it was out of the boat, one while still in. The one that was still in the boat we used a siphon pump on it, then pulled the drain plug and very little oil came out, maybe a couple of drops.

I was actually surprised, we still put the drain hoses on but still used the top-side pumps after we saw that.

good luck on getting the hose thru the drain plug if its a single engine boat....NFW on mine...