F225 overheating

[gator05301]

Started motor after 2 month layoff with muffs on before going out. Good thing because no pee flow and thermostat flow never kicked in. Replace water pp impeller; housing had a good bit of melting so I replaced everything. Still no cooling flow and got hi temp alarm. Removed thermostats; not great but they don't look that bad. Will replace them. Not sure if this is the right test or not but I hooked up the muffs to see if I could get flow out the open thermostat housings. None Ran the motor with thermostat housing off..no flow out housing or pee hole. So;
1. any thoughts on what to do next
2. I'm not sure if blockage is my problem but what is the proper way to test all portions of the cooling system to ensure I have no blockage anywhere?

[gator05301]

It's looking like some kind of blockage somewhere. Took the foot of, pump housing overheated again. There's a lesson, it doesn't take long. The alarm hadn't sounded 2 seconds before I turned the engine off. With little or no flow, I'm guessing damage to the housing occurs even before alarm is recieved. Anyway with thermostat housings off, foot off, flush line off and directing hose in water pump discharge line (engine uptake) I get no water out of the thermostat housings or out of the flush line. Looks like all the water is going out what I assume are cooling channels around the exhaust. Flushing from the flush connection I get a good bit of flow out the thermostat housings (engine side) as long as I keep the water pump discharge line plugged. (Without plugging all the flow goes out the line). So I guess I'm onto my second question above; I need to map out the cooling system flow paths and come up with proper way of clearing/flushing the various flowpaths. aarrgghh! side note.. I'm still getting no flow out of the pee line by flushing either way. The line is clear all the way to where it connects on the front port side of engine (ran stranded leader all the way). There's another line coming off the same block the pee line connects to that runs around and in the back of the engine. Disconnected it and got solid flow
Anyone have something they can offer...I'd be grateful

[99yam40]

maybe the PRV is stuck open dumping too much water into the exhaust, but that would not fry the pump housing

[tainted1]

Couple of thoughts.

I have to tilt my F225 before I can get it to pee while running on muffs. Others have said the same. Your domestic water pressure may not be high enough to prime the water pump. This would be my first guess as to why the housing is melting.

I'm sure you're aware of the F225 exhaust corrosion issue. It is possible that your exhaust components have corroded through allowing the cooling water to bypass the engine and go straight to the ehaust. Looking up the exhaust with the foot removed, do you see a black uneven surface with white marks or crystals? If so, corrosion may be your issue. Check this out F225 Corrosion Fact Check - The Hull Truth - Boating and Fishing Forum

[gator05301]

Actually I just crawled out from under a rock apparently. I wasn't up on the corrosion issue. Looking up the exhaust, I definitely have a good bit of white corrosion spots as far up as I can see. So now the question is is this part of my problem? I'm thinking not as I wasn't having overheating problems, never got an overtemp alarm at speed or when bringing back to low RPM's. Damn I don't know now. Maybe something suddenly gave out. Could this issue cause complete and sudden loss of flow to the head?

[rodbolt17]

2 melted housings.
tells me either your muffs dont fit tightly to the gearcase OR your water supply pressure is to low.\
use the builtin flush hose and dont run it above idle.
and quit chasing ,yet.