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Water pressure through block
Raw water cooled 350 gm. Omc cobra
curious if someone has a spec for how much water pressure, is normal I dont presently have too much or to little but have been searching for weird water accumulation in bilge. But was not finding much Yesterday while draining the blocks And system for impending freezing weather I noticed a very heavy rust stain at elbow to exhaust manifold interface... Was musing if this could be spraying or leaking under higher rpms..3k I orderd gaskets But Since these are original 1988 manifolds of fresh water use only I may end up ordering new manifolds etc But thought... How much water pressure is normal Book is absent on details... |
I would be concerned that the manifolds are corroded and leaking water into the exhaust port/cylinder.
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2psi at idle up to about 30psi at WOT is pretty normal
Do you have a water pressure gauge installed?? |
Originally Posted by Griff
(Post 4938078)
2psi at idle up to about 30psi at WOT is pretty normal
Do you have a water pressure gauge installed?? But was curious A few things I have to change is 180 t stat to specified 160 I drained and pulled all hoses yesterday from recirculation pump, and manifolds very light brown wayer poured out I have a borescope coming I am hesitant to dump tons of money on 37 year old engines But they run great, only light smoke from cold start Very strong ppwer 855 hrs total Manifolds are easy fix stock manifold and riser is 700 to 1k per side or Eddie marine has alum high rise for 1700 a pair Leg is in a cast so mt time in engine bay has been really cut back was counting on oct getting all fluid Etc done and put some hours on her to help plan next steps Boat is Very very well tsken vare of rig |
The elbow to exh manifold gasket leak is very common. As mentioned...the bigger issue is water leaking into the manifold exh passage into the cyl head ports.
With the raw water just exiting into the exhaust stream in 12" with relatively open ports, you won't have as much pressure at that location, even at max engine rpm. The pressure is all added up from the complete system restrictions at the input hose, reducing pressure as it flow through. When you pull the risers off, you'll see how healthy they are. What the mating surfaces are like etc. Make sure you put the gaskets on dry...silicone will push them out...and leak. |
Originally Posted by Tartilla
(Post 4938103)
The elbow to exh manifold gasket leak is very common. As mentioned...the bigger issue is water leaking into the manifold exh passage into the cyl head ports.
With the raw water just exiting into the exhaust stream in 12" with relatively open ports, you won't have as much pressure at that location, even at max engine rpm. The pressure is all added up from the complete system restrictions at the input hose, reducing pressure as it flow through. When you pull the risers off, you'll see how healthy they are. What the mating surfaces are like etc. Make sure you put the gaskets on dry...silicone will push them out...and leak. Proof will be in the pudding once the riser is detached...if its eaten or close to its limit Replace all four for sure |
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