250 pxs 4S over heat

[Travis]

2023 250 pro xs
12500033A / 3B264559
Ran in some bad water couple weeks back and lost water pressure at gauge. Never had a temp issue so figured line to the gauge was stopped up. Fished another tourney and ran fine all day. Always let the t stat open which it always did around 140 and would drop back before I would ever get on plane. Well made it back to the ramp and while waiting on the trailer it ran up to 200+ and alarmed. Came home cleared h20 line, replaced water pump and t stat. All gaskets where in great shape. Only 76 hours. Well, now still no water pressure... Installed sendor that plugs to harness and t eed it in with water line. Even with it... No water pressure. Just trickled out from block port with line off at idle. Still wants to run hot but then out of no where will run 130s and ride for awhile. What gives????

[mactlman]

clean out the filters and strainers?

[Travis]

Checked all three. Clean as can be.

[thommo59]

Try the coastal flush on the side and give it a good flush without the engine running

[Travis]

Did that too for 15 minutes

[EuropeanAM]

2024 250 pro xs
12500033A / 3B264559
Ran in some bad water couple weeks back and lost water pressure at gauge. Never had a temp issue so figured live was stopped up. Fished another tourney and ran fine all day. Always let the t stat open which it always did around 140 and would drop back before I would ever get on plane. Well made it back to the ramp and while waiting on the trailer it ran up to 200+ and alarmed. Came home cleared h20 line, replaced water pump and t stat. All gaskets where in great shape. Only 76 hours. Well, now still no water pressure... Installed sendor that plugs to harness and t eed it in with water line. Even with it... No water pressure. Just trickled out from block port with line off at idle. Still wants to run hot but then out of no where will run 130s and ride for awhile. What gives????

Did you replace the GASKETS, and apply perfect seal to the bottom of the impeller (upper) gasket?

Have you re-checked the thermostat for debris, and tested to make sure it opens correctly AND CLOSES correctly?

Side note: Mercury doesn't use years... your engine was built 9/22.

[Travis]

I triple checked the water pump and gaskets. I didn't apply any sealant as I read not to and there was none on original. I've got another water pump kit on the way. What sealant do I need to use?

[EuropeanAM]

Perfect Seal, which is simply Permatex Aviation Sealer.

Make sure you're testing water pressure with the boat in the water (not on a flush attachment).

[Travis]

My dealer says not to use the sealant..... and that I more than likely have a blockage in the coolant system somewhere. So use the sealant? I flushed it but maybe I should flush with the T-stat removed and do it longer after I install the new w/p kit? Boat in the water, I have ZERO water pressure. Pulled the water line off the block at idle it barely dribbles out while running. So I feel you feel it could be the water pump sucking air at the gasket or just blowing out? but both gaskets looked great. I am just at a loss with it. I thank all of you for yalls input.

[Travis]

And yes I replaced the gaskets and I have pulled the T stat again and see no trash at all.

[Travis]

Also the pee hole water never gets warm

[EuropeanAM]

My dealer says not to use the sealant..... and that I more than likely have a blockage in the coolant system somewhere. So use the sealant? I flushed it but maybe I should flush with the T-stat removed and do it longer after I install the new w/p kit? Boat in the water, I have ZERO water pressure. Pulled the water line off the block at idle it barely dribbles out while running. So I feel you feel it could be the water pump sucking air at the gasket or just blowing out? but both gaskets looked great. I am just at a loss with it. I thank all of you for yalls input.

Someone might need to update training a bit there.

Don't overlook the water INLETS (not just the side ones, but also the low water inlets). Make sure no debris is present.

Also check the pump housing to water tube seal/adapter to make sure it's making a seal-tight connection.

You could also connect a garden hose to the Coastal Flush Adapter, turn the key ON (don't start) and see what you show for water pressure.

[Travis]

I have the sealant coming. Unfortunately I've broken a threaded insert on the lower cowl and I'm waiting on that part before I can install that but I can still check the water pressure as you said. Can you tell me where exactly the sealant is applied?

[Travis]

Did you replace the GASKETS, and apply perfect seal to the bottom of the impeller (upper) gasket?

Have you re-checked the thermostat for debris, and tested to make sure it opens correctly AND CLOSES correctly?

Side note: Mercury doesn't use years... your engine was built 9/22.

So Do I apply the permatex to the last gasket to go on before the housing? Just the bottom? Please help me out to understand this.

Thanks

[EuropeanAM]

Travis- the underside of the top gasket: Most specifically between the two bolt holes that face aft (the gasket has a natural hump or bulge here). If you apply to the entire underside, make sure it's not thick enough to get into the impeller/plate area.

The area between those two bolts is the only area critically needed, and this helps to reduce the odds of the gasket "blowing out" in this area when the gearcase bounces in/out of the water.

[Travis]

So hooked up to the flush and plenty of water pressure on my hose bibb but I have zero... ZERO water pressure on the gauge

[Travis]

Should I have pressure on the coastal flush hook up?

[Travis]

Someone might need to update training a bit there.

Don't overlook the water INLETS (not just the side ones, but also the low water inlets). Make sure no debris is present.

Also check the pump housing to water tube seal/adapter to make sure it's making a seal-tight connection.

You could also connect a garden hose to the Coastal Flush Adapter, turn the key ON (don't start) and see what you show for water pressure.

So the I changed the water tube seal o rings and they all look good. When I removed the L/U it stayed stuck up on the midsection but everything appeared to be good. My concern now is that even tho I see NO debris in anything, that I still do not have water pressure on the flush. Should I? That tells me it is not a w/p gasket issue. Correct? My dealer says this is not going to be warranty work If i carry it in. What in the world am I to do?

[EuropeanAM]

Pull it down again, change the upper gasket, and make sure you bring the screws down EVENLY by hand, with a 1/4" drive ratchet. Use that until they are evenly snugged, and then torque to specifications.

If one of the bolts gets well ahead of the others, the pump housing and gasket may not seat properly, resulting in low water pressure at idle.

[Travis]

So I shouldn't expect water pressure on the hose just running the flush?