mtgbiker

I want to use this set-up for my rebuilt hp420's....now 511/514hp. The hp500 set-up uses 2 by-pass valves. One at the block and one on the remote filter mount. Will a Mark 4 block accept the valve at the block?

mtgbiker

After additional research, the Merc diagram list 2 valves. I would think one valve at the block would work using a standard remote filter head.

However, when using the thermostat HP remote head, do you need the additional valve there too?

Someone please help a brother out!

RLW

I am under the assumption that you are using the remote Mercury Racing Oil Filter T-Stat mount. If you are indeed using that setup, you can remove the bypass at the engine block filter pad and plug it. This will force all the oil to the remote filter mount. The bypass at the filter mount will do it’s intended job, if required. This setup insures that all of the oil goes to the filter. I am using a Dart Big M block which is based somewhat on the Mark IV block with a priority oiling system that is incorporated in the Gen 5 or 6.
I have plugged the block bypass and rely on the filter mount bypass (Mercury Racing HP500 style).
Hope this helps or maybe generates some other opinions.

mtgbiker

I am using the remote Mercury Racing Oil Filter T-Stat mounts as you describe off hp500 carbed motors. Not sure what year though. Out of curiosity, what temp stat is used in these set-ups? I would think a minimum of 220* since water boils off at 212*.

Does Merc run 2 bypass valves in the gen 5/6 blocks? According to the Merc diagram, they require 2!