stock 500hp set up how do i add a oil cooler t stat, mine never gets to 200.

A picture is worth 1000 words so here it is...

Oil goes out of the block (yellow path) and if hot (red path), gets diverted at the T-Stat to the Cooler, on return it is sent through the filter then back to the block. If cold, (purple path) the oil goes straight to the filter then back to the block until it heats up.

Thanks to Articfriends for the pic, I constantly use it as a reference and standard now!!

Hope this helps!

Where is the temp being taken from???????

If it never hits 200* then you would be getting condensation in the oil. Get an infared temp gun and point it at the oil pan.

I am getting condensation and it does not go over 200 ,, i just ran a 20 plus mile run at 3500 to 4500 rs and 195 was the hottest it got.

The oil cooler is big enough, but you are going to need a oil thermostat to get the oil to 212+ at the RPM you just ran. The thermostat restricts the oil flow until you build heat, then it starts to open. I expect you could build oil temp if you run at 4500+ RPM for 3-5 min. If you aren't up for the cost and rigging work for an oil thermostat, just occasionally run for a few minutes at an RPM level at gets you to to 212+ to cook off the moisture.

just looked on mercruiser site shows a picther of a t stat going into the oil filter block, is that maybe what i need to change.

For example:

http://marine-performance-parts.com/22480.aspx