Hi, how have you improved your stock merc pump for external hyd steering? Found an old thread were was recomended to enlarge the pressure side fittings orifice to 3/16", to get more volume and lighter steering at low rpm.

Didn't do anything to mine other than plumb it when I installed hydraulic steering. I have dual ram single drive and it steers like a dream. I think if it won't maintain pressure at idle you have a bad pump and you're just masking it with the larger orifice but I could be wrong...

Mine is also going to be single drive dual ram. 160cc orbitrol, 9" stroke rams. Good to know that it works perfect with stock pump.

Mine is the standard saginaw I think it is v belt pump...I am currently in the middle of swapping to a serpentine setup with the stock 500 efi PS pump and have seen hundreds of boats running hyd steering with that pump too.

I was too quick and allready enlarged the orifice to 3/16", this mod should only make difference at low rpm operation. You can also adjust the pressure with shims.

I bought a Jones racing pump recently, they make them with remote resevoir or built in.
Small and compact, havent used it yet.
My old GM standard autoparts store pump worked just fine too, just bulky and it the way of my new idler

I drilled my pump orifice but cannot recall exactly what I did. The system works great but I do not have a before and after comparison.