Gil manifold plumbing
 

Is there a better way to plumb the water feeds to the manifolds? The way this boat came to me there are the two lines connected to a Y which then is connected to the bottom of the exhaust manifold.
I've seen other set-ups were the tee it at the riser.
http://s101.photobucket.com/user/con...?sort=3&page=1

Two chouces. That is the old style thermo housing with 4 outlets. Replace with new style with only 2 outlets. Your Gils. There are 2 water hoses going from man to riser? 1 in front, 1 in back of riser? If so, you could cap the front outlet from manifold and run the top t Stat hsg outlet to front riser inlet. The rear manifold to riser hose should be plenty for the rest of water flow. But the setup you have now is fine, just kinda ugly-cobbled together looking.

you have a restriction kink in the T stat hose. I would address that.

As mentioned there are two main ways to do it:

1. 4 port t stat with y pipe plumbing. Similar to what we have

2. Replace t stat with 2 port plumbing.

http://i.imgur.com/oHhCaEU.jpg

The other alternative is weld another bung into the top of the riser but I think it would look worse than what you have now.

Factory Merc Racing with Gil's and the 4 outlet Tstat housing used a T at the top of the manifold just before the riser.

Nice setup. Cleaner than what he has and doesn't mess with manifold water flow like my idea.

I'm aware of the kink, this is why I want to change things.
Found the Gil instructions online and they show my set-up but the wye is much closer to the bottom of the manifold.
The tee fitting Griff shows I like. Seems it would keep the riser cooler than the flow just coming thru the manifold. I may have a set of them somewhere. They came with a set of manifold I bought used years back. I'll have to look.
Thanks to all

My 420s are the same setup as Griffs pic

Found a parts view that shows the tee. #4 At that price I'll turn the shop upside down looking for them.
Genuine Mercury & Mercruiser parts. Exhaust Manifold / Elbow(425 GIL System)