zz28zz

Did you check the fitting where the water pump inlet hose connects to the drive? I assume it was disturbed during eng R&R. I believe it's plastic and I've heard of them cracking/breaking. If cracked, it might be allowing air to enter system. A big air pocket at the top of the risers would explain the symptoms.

You could temporarily install clear tubing in series with or in place of the various cooling hoses (not pump suction hose) and see if there's lots of air in system.

underpsi68

Also make sure all the hose clamps are tight. It will suck air especially at idle.

EMARTELL65

The transom fitting attaching the raw water hose came with the new transom assembly that was installed. I’m going to replace the collapsed hose this weekend and check it again on the hose. Most people say I should be able to place my hand on the top of the riser while idling and should not be hot. Has anyone else found this to be the case.

underpsi68

Yes you should be able to keep your hand on the riser at idle or speed.

BUP

iTrader: (9)

I have not read too many of the posts here so maybe I missed a bunch. Anyways lets back up for a bit - which engine do you have ? year model - stock or ??? how is the cooling set up ? Which water impeller pump do you have ? How old is your water circ pump ?? how old is your T stat ? or are you running a crossover ?

Have you installed clear water hoses to see water flow and check for air bubbles in the water flow stream ? You start at the inner transon hose then do this in sections and keep moving forward to find your water flow issues. This is how marine techs find cooling issues in a matter of mins to a couple of hours max. Also performing water output tests in the lake or ocean .

Next important question is --- Do you have closed cooling ?

AllDodge

iTrader: (1)

Say good night Gracie

EMARTELL65

The engine is a 500hp DPX with closed cooling. The issue is with the raw water side. The engine temp never exceeded 130 with the cold water temps (Lake). Which would lead me to believe the circulating pump is fine.

BUP

iTrader: (9)

not knowing your set up and I think not many others know either - its a DART throwing contest all day long.

Change your end cap sealing gaskets in the heat exchanger and clean it out 100 percent. This is why I asked about your set up. Your pic does not show what exactly you have. Just saying.

temp readings on the dash has nothing to do with waterflow to the exhaust nor water flow thru the engine. zero. A coolant temp sensor can possible read extremely low without any water flow passing over the sensor portion. It can not read air nor air bubbles for a correct temp reading.

Also the crank impeller housing will wear out over time. Have you done a water out put test after the impeller ? And like I said clear water hose testing to check water flow and water aeration to pin point the area where the issue is.

GLENAMY 242SS

iTrader: (1)

Look at my port water outlet from manifold. This is a simple clear hose tool for checking water flow/air bubbles in the flow. It can easily be moved to various locations to check status.
I have used 2 or 3 at a time to save the effort of moving it. I call it my "Water Window"

zz28zz

I should clarify what I said prev abt not using clear tubing on raw water pump inlet. If you install clear tubing on the pump inlet, be aware the OEM hose stiffness is waay higher than clear tubing and.there's a risk of it collapsing, blocking water flow and cooking the water pump impeller in a matter of seconds. Lots of variables to consider like type of material for the clear test hose, temp, hose wall thickness, performance of raw water pump, garden hose supply rate, etc. Bottom line is if you install clear hose on pump inlet, keep a close eye on it, especially if you raise eng rpms even a little bit.