risers on a closed cooling system

[boatingfool]

What do I have in there? Raw water passing through or the mix?<br />I have followed the raw water tubes and one tube comes into the top of the heat exchanger and then another tube also comes out the top and the tube follows the riser (runs underneath it) back to the transom. then the riser and tube come together where they enter the out drive.<br /><br />I cant see how the raw water would get into the riser ??<br />But I was tinkering with the boat the other day and ran my finger across the riser drain and it had clear water drop(no green at all) with a little rust in it formed up on the bottom of the drain.<br /><br />So whats in there??

 

[johnkc]

Re: risers on a closed cooling system

uhmm? i will take a guess on this one since i don't know what engine you have and that you got water out of the riser.i would say that the engine only is closed cooled and the manifolds are cooled by the water that has already made a pass thru the heat exchanger.

 

[boatingfool]

Re: risers on a closed cooling system

johnkc,<br /><br />volvo aq 125.<br /><br />I have had the heat exchanger off and the raw water does not enter manifold from there. Only one inlet and on outlet.<br />Thays closed cooling in, closed cooling out .the heat exchanger raw water outlet tube runs underneath the exhaust manifold.

 

[Boatist]

Re: risers on a closed cooling system

Boatingfool<br />All I can say is I never seen a system that did not have raw water in the riser. Half systems only do engine not manifold. Full systems do Engine and Manifold but not riser. Find your Brand and model number and look them up on internet or give them a call. If that is a 4 cylinder I have never been able to find a full system that protects the manifold.