Can some please explain Proper water flow?
 

I have a 1994 5.7L mercruiser with alpha drive gen 2. I get a lot of water out the 2 transom ports but very little out the propeller exhaust. Is this proper or is perhaps something about clogged up. I'm not really running hot but I do believe I'm running warmer than it should. Has new thermostat, water pump and impeller. All quicksilver brands. Thank you 😁

Why do you think you are running warning? What is the temp of the engine?

I posted my temps in another post. I get a random alarm on occasion that goes away when I idle down. Some responses claim my temps are normal at the following values: After replacing my 140 deg thermostat, My exhaust manifolds and elbows was reading the following temp with ir gun after running 2 miles on the river.
Starboard Manifold - 175/Riser - 115.
Port Manifold - 170/Riser - 104. Temp gauge reading 160. I get tons of water flow out of the 2 holes on the transom but I feel like water flow could be better out the exhaust at my prop. Maybe the water exit at the prop is suppose to be very minimal. I don't know. I guess I'm trying to figure out if the 2 transom ports are actual exhaust or just the elbow discharge and if the exhaust going to the prop is for the actual engine

If you’re getting tons of water flow out of the dumps and you’re sure that’s last in line I wouldn’t worry about how much is coming out of the prop, particularly if the dumps are past the temp gauge sensors which they SURELY should be.

Are you SURE you have good flow? Even with new pump and impeller you don’t have any blockage? Transom assembly water hoses are notorious for corroding and causing poor water flow…..

do temps keep building or just plateau at 170?

blockage in your coolers? You can back flush them if needed.
ABSOLUTELY sure it’s a 140 stat? Wouldn’t be the first time I’ve gotten a mismatched part in the box.

Is this on the hose or boat in the water?

the temps are boat in the water

not sure about good circulation but I feel I have plenty coming out of the dumps even on garden hose. But possible I have a blockage that's starting to happen. I ran the boat on the river for about 2 miles, temps went up on the manifolds to the 170's. Ran another 2 miles and they stayed the same. I guess my next order of business is to figure out the where the transom assembly water hose. Are the coolers the elbows? This setup doesn't have risers from the manifolds to the elbows. That's the info I guess I was looking for

I was referring to coolers for things like oil, power steering, fuel coolers, etc…..

I forgot this was an alpha so I’m not sure water flow through the Transom Assembly on that model, but I still think it comes up through the transom assembly and likely has a hose that can constrict…..

Sounds like a non issue to me if you ran 2 miles and temps stayed at 170

it's what I been told by forum members but I still get the random warning alarm. It's a very low sounding alarm that comes on. Not as loud as when you just turn the key on. I'm just trying to understand the water flow through my system so I can just go through it to make sure all is good. But maybe it is fine. As mentioned, I get tons of water out the dumps

Alpha system:
Outdrive pump, to transom thru small diameter (5/8” ?) hose. Inside boat, top of transom plate, there is a nipple fitting bolted to top. Hose connects to this, routes under motor on passenger side , just after motor mount it will go to power steering cooler. Hose goes from this up front if motor to the thermostat housing. Housing will prioritize water going to engine (recirculating pump) and the remainder to the exhaust. When engine thermostat opens, that water will also get routed to the exhaust. Since tstat prioritizes engine, more water will thereflow flow to engine with tstat open.

https://cimg0.ibsrv.net/gimg/www.off...ce7dc28a63.gif

Once water enters the y pipe it will take the path of least resistance to exit the boat depending on boat angle, drive angle, pressure, etc. The exit locations are the 2 holes on the transom assembly and through the prop.

Found a water flow chart that shows what I explained: (most older engines don’t have a fuel cooler, but have ps cooler where fuel cooler is in the chart)

https://cimg5.ibsrv.net/gimg/www.off...b7f5e168a.jpeg

this information is perfect. It gives me something to focus on and track down. Before this I was at a loss. Thank you so much

also,,take close attention to the thermostat,,you wouldn't be the first person to install it wrong.

I'm almost positive I had the spring facing down. And I know the plastic retainer is installed right. I made sure the ports wasn't blocked by the plastic retainer and besides that, it's notched and grooved to only go one way

https://cimg7.ibsrv.net/gimg/www.off...86723c58a7.jpg
up there on the risers are the rubber boots that connect to the Y pipe, up near the top of the Y pipe are some flappers on each side.
Every once in a while they deteriorate or fail in some kinda way in which all or part of them end up as far as the drive.
only way to find out is remove the boots and scope the Y pipe, next would be to pull and split the drive.
Some shop putting in an impellor doesn't mean anyone looked any deeper if there was no complaint
New flappers doesn't mean the old ones or part of the old ones aren't jammed up somewhere down stream.