I recently purchased Hardin's replacement for the GiL HP500 9" riser. I have never seen the small 3/8 fitting on the underside, and I'm not sure where I have to plumb it.

Hardin told me Gil added these to the HP500 and 525's, but I can't find any picts where this should be plumbed, no schematics, no text.

Where does this get plumbed, to the sternside on the water rail (small 3/8" plug), or the sternside of the upper manifold (3/4" plug)? The fitting itself takes a 3/8 hose, so I'm thinking to the water rail.

Also, what is the purpose for this extra fitting?

Thanks in advance.

That's the steam vent. It get's plumbed straight down to the back side of the Manifold (at least on the Gil manifolds). The hose is only about 3" long on mine.

It attaches where the 3/4" plug is. You just need to get fitting to reduce it to a 1/4.

Thanks guys. So it goes to the 3/4" on the top of the manifold, opposite the normal hose hookup. Any pictures? I'm thinking -6 (dash six) braided hose would kind of dress it up a bit.

And the fitting I'll need is 3/4 pipe thread to 1/4? Hardin said it uses 3/8" hose.

Shouldn't you be leaving all this technical discussion to your crew chief?

Hmmmm, everyone told you the same thing I've been telling you ALL week.......geeeesh don't ya trust me anymore ? Lol

He did, we discused it all week!!

It's a little late for him to lose faith in you now



Well, those high paying performance boat guys are always a pain to work with......

BTW Gary, 17 posts, after those 2, you are just setting this place on FIRE! Cut back a little wouldya

And still not 1 picture, schematic or diagram of the setup from Merc, Gil, Hardin, or community. This must be a great kept secret.

Hardin sells a kit for it with hose and fittings to make it easy, maybe it will make more sense to me when I get it. But of course they don't have it listed or pictured on their website. DOH!!!