Exhaust manifold replacement

"In previous post I mentioned

"In previous post I mentioned weeping resevoir cap...That's remaining stable however my temp is 210 degrees @ about 3000 rpm's.New hose connector,new raw water pump but...
I think the back pressure in my 125 aq a's is due to the exhaust manifold needing replacement.
That being said,on the OSCO vo418,a replacement mani with "improved water capacity",pencil zincs,lifting ring...will that mani. outperform standard Barr option...I want to get out of this hot water!!!Help"

"Michael,

I would suggest

"Michael,

I would suggest that you remove or slide downwards the exhaust hose (part 18) and slide a small screwdriver in the water passages. If they are clear, chances are the manifold is not the problem. You may also want to verify that the connection for the copper pipe under exhaust manifold connection for the copper pipe is clear as well. If you connect a water hose, you will see if there is back pressure and how much water comes through the cooling ports."

"Thanks El,
I'll get into

"Thanks El,
I'll get into all that Friday...today removed exhaust mani on my "old"spare engine,I was going to have it boiled but it was too far gone.I've got to be close on getting this all right,unfortanetly I'm way too intimate with the linear flow of water in this engine,components of the cooling system and how it all affects performance...That mani. is just about last in the line of things to shake out "

"Look at it from the positive

"Look at it from the positive side. Once you replace it, if the problem persists, there is one less thing to look at. "

"Yes,I know I've got to be

"Yes,I know I've got to be close to sealin' the deal.I'm going to probe about and see what kind of build-up(rust,crud,sea urchins and the like)is around the mani.that's on my boat checking for obstructions etc...That being said is there any diff.as to performance and longevity for the array of manifold options out there.The one I was going to re-use was less than 3 yrs. old.And that was no good...My boat sits at mooring for season(finally got in last week,hooray)in salt water in the Northeast,if that makes any difference...Or do I assume that I'm changing out mani.after 2 seasons.Thanks El and all for answers to my questions in the past,present and future(hopefully not too many of those)...Mike"