2019 250 pro xs V8 waterpump question

[fuelleak]

Ser# 2B571507. I put a new impeller and gaskets in my motor. Used the old stainless base plate because it had a deflector and the replacement didn't. It did show some wear on the surface. Also used the old housing which looked good. Put it back together and now have no at idle water pressure and will eventually overheat. Pressure will eventually come up with rpm and motor will cool. Comes up jerky on the water pressure gauge also, not smooth like before. Put the old impeller back in, reused formerly new gaskets and its still doing the same thing. I was told the new kit I had from my 2013 Pro xs with torquemaster would work with the 2019 with torquemaster. Saw baseplate was different after I got L/U off and was worried about using it as it lacked the deflector. Does anyone have a clue as to what I did here? Can I use the base plate that doesn't have the deflector? Is the worn baseplate my issue?

[EuropeanAM]

Depends on how "worn" the impeller plate is.

Your engine, and your previous engine BOTH use the same (8172761) impeller plate. Not sure what you are referring to as a "deflector".

What did you use to lubricate the impeller fins?

And what direction did you turn to fold impeller blades ALL in the correct direction?

Either something is not right in the water pump, OR there is a leak at the water tube coupling.

[Bartman]

Are you checking it with ear muffs, in a tub or on the lake? Trust me, it makes a difference!!

[fuelleak]

Don, impeller plate on my 2019 has a plastic wedge that looks like it directs water upwards into the water tube. I see the deflector on the faceplate when I go to the schematic for my engine. The face plate that came with my kit for the 2013 was flat. I turned the drive shaft clockwise to seat the impeller. Put a super light coating of Merc grease in the water pump housing. Bartman, this is happening out on the lake.

[EuropeanAM]

I see what you are speaking of based on the picture in the Parts Catalog, BUT the Part Number used is a FLAT plate. There have been some subtle changes to the water pump kits since your engine was produced, this likely being one of them (I've got three of those engines here right now, all have flat plates, Part# 8172761 in them).

[fuelleak]

Thanks Don. Still having a over heat problem at idle after trying the flat plate. So weird that if I take off when I see the temp start to climb the motor cools down and runs at 138 degrees. I also had two hard misses while running at 5500 rpm at one point, then it ran fine. That was odd. Not sure if its related. Off to the dealer on Tuesday.

[EuropeanAM]

Wondering if your thermostat might simply be sticking.

[fuelleak]

Follow up: Mechanic did a bit of head scratching, called Mercury and they advised to take mid section cowling off and see if a hose may have become disconnected. Mechanic did that and there was the disconnected hose. Reconnected and all better. It was coincidental that my impeller change and that hose popping off shortly after had happened. Except for the fact that I took that L/U off 10 times trying to figure out what I had done wrong, nothing drastic with the motor.

[EuropeanAM]

That's good news!

Any chance you can find out specifically "which" hose had come off (there are a few down there).

[fuelleak]

Ill see if I can get an answer from the mechanic. I was told by the front desk service girl that my water strainer/filter was pretty full of junk also. Don, is it easy for a DIYer to get to that filter? I asked her and she said it was a big job. I didn't even know there was a filter under the mid cowling. My upper two strainers were perfectly clean when I checked them during this problem.

[EuropeanAM]

There is a third (3rd) exhaust strainer located under the port-side lower cowling. Once the cowling is off it's not too bad to get to, but it will take a while to get that cowling off for access.

[fuelleak]

Thank Don as always!

[fuelleak]

Update #2: Well I reloaded the boat with all my gear and took it to a local lake to test today. Started motor, idling in neutral only and watched the temp go up and up and when it hit 180 I turned it off and called the mechanic. he's looking at it again in the morning. What in the world is going on?

[EuropeanAM]

Water tube connector damaged?

[fuelleak]

It looked fine to me Don. Seems like there isn't water getting to the upper block as the motor temp climbs very fast. Again this is only at idle.

[EuropeanAM]

I'd be interested in more info on this "hose that came off". Can't help but wonder if it's a repeating problem.

[fuelleak]

Haven't heard anything for a couple days from the marina. Ill give you a heads up once I get some info.

[fuelleak]

They now have a Mercury service tech working on it today, still haven't heard anything except for that tidbit.

[fuelleak]

Mercury is now suggesting that the exhaust passages be looked at. Suspecting a casting flaw that may have let loose. Tests are verifying that water pressure is adequate. Mercury says this is a first for them.

[fuelleak]

Well it turns out that the water pump kit from older torquemaster lowers on Opti's have a slightly different gasket under the wear plate which allowed exhaust gas to enter the water stream at the pump only at idle. The mechanic at Woodards marine finally realized it after opening another water pump kit and noticed the difference. Quite the ordeal. Don, the hose I was told directs water to the upper motor mounts which are water cooled? Does that sound right? I was also told that there are sprayers that are directed into the exhaust tube from those mid section hoses.