More Overheating helps

[novas_searay215ExpCrus]

So sports fans. I have replaced the impeller, the water pump, the sensor units, and the thermostat, and replaced the original wet joint manifold/spacer/and riser with a brand new Dry Joint Manifold manifold/spacer/and riser. Also replaced the plugs and cables, while I had the manifolds off, so this boat sounds amazing... But she is still overheating and I am lost.
Yes, I backflushed the system too. Also, the Manifolds are getting hot too like water is not getting to them. I need help, any ideas? Could something be clogged in the upper stern drive unit? Or the barrings under the impeller shot?

 

[Lazy Daze]

Can we assume this is the boat in your signature?

Did you only replace the impeller or did you also replace the wear plate and housing? If there is ANY scoring in there, it can affect water flow.

Back the boat into the water at the ramp and disconnect the water inlet hose at the t-stat housing. Run the hose and collect the water that comes out in a bucket and measure the amount. Collect for exactly 15 seconds with the engine at 1,000 RPM's. Repeat two or three times for good measure. You should see between 3 and 4.5 qts, depending on your gear ration. If you get near that amount, you've got a good impeller/housing and no obstructions.

 

[jmcdboater]

Wow, @Lazy Daze, that’s some crazy good technical help!

 

[Bill Curtis]

Depending on his installation, the raw water system may have that bypass thing in it. If it does, could be stuck. Many threads on it.

 

[novas_searay215ExpCrus]

Yes, that’s the boat, and there’s no scoring. Here is something I think I missed too. I have a closed cooling system, when I hook the muffs to the stern drive it is driving water just fine, because it is pumping out a tube in the top of the stern drive, with great force, so the impeller is good, and the tube is not connected to anything. I disconnected the raw water hose and flushed the system and it was clean. So I had this rocket science moment does the back of the boat needs to be in the water for the closed cooling system to work since the impeller is not pumping water into the cooling system? OR is there something else I am missing?

 

[Lazy Daze]

Yes, that’s the boat, and there’s no scoring. Here is something I think I missed too. I have a closed cooling system, when I hook the muffs to the stern drive it is driving water just fine, because it is pumping out a tube in the top of the stern drive, with great force, so the impeller is good, and the tube is not connected to anything. I disconnected the raw water hose and flushed the system and it was clean. So I had this rocket science moment does the back of the boat needs to be in the water for the closed cooling system to work since the impeller is not pumping water into the cooling system? OR is there something else I am missing?

I'm not following what you're saying. This "tube in the top of the stern drive" sounds like the vertical water tube. But that is only accessible when the lower unit is split... which means the impeller is inoperative at that point. It CAN'T pump water if it's not connected to a running engine.

I also don't know what you are asking (in bold). HOWEVER, you shoudl be able to run the engine nicely whether it's in the water or on a hose... assuming you have good water supply through the hose.

Do the thing I mentioned. But instead of your t-stat housing, the water inlet hose is at your heat exchanger.

You can also pull the heat exchanger and check the interior passageways.

 

[novas_searay215ExpCrus]

I needed an inboard flush thing that goes over the raw water intake because the impeller is not connected to the engine the water going into the impeller is just cooling the stern drive. I checked all the interior passageways they are clear. I replace the water pump, but not the raw water pump, and after hooking the plunger thing to the raw water intake it is not taking water in at all.

 

[novas_searay215ExpCrus]

When you know it's the raw water pump!

 

[Lazy Daze]

This is confusing because key information has been left out a couple times. It's still not clear. Please describe your cooling system with some specific detail (the pieces that make up your cooling system) and also list exactly what you replaced. For example, in your first post you said you replaced the impeller... but now it seems you did not?

 

[Bill Curtis]

I see what he's saying. He has a thru hull raw water intake, a raw water pump in the engine compartment and the Alpha pump hose from the drive to the transom plate is disconnected, hence the water squirting up when on the muffs.. I just saw the pictures, that's a Bravo raw water pump.

Is that a Bravo engine pushing an Alpha drive?????? Or is it a Bravo drive.

I may have this all wrong, but the description is sketchy at best. The pic is worth 1000 unclear words..

Now, if he ran the engine with the hose connected to the drive and nothing to the thru hull intake, then that raw water pump is toast, AGAIN..

 

[Lazy Daze]

I see what he's saying. He has a thru hull raw water intake, a raw water pump in the engine compartment and the Alpha pump hose from the drive to the transom plate is disconnected, hence the water squirting up when on the muffs.. I just saw the pictures, that's a Bravo raw water pump.

Is that a Bravo engine pushing an Alpha drive?????? Or is it a Bravo drive.

I may have this all wrong, but the description is sketchy at best. The pic is worth 1000 unclear words..

Now, if he ran the engine with the hose connected to the drive and nothing to the thru hull intake, then that raw water pump is toast, AGAIN..

OK, your "guess" on what he's saying makes sense

In that case, somewhere along the line, someone added the Bravo raw water pump to his engine. Engine's aren't really a "Bravo or Alpha" - it's just a matter of bolting on the Bravo pump to the engine and adapting a new serp belt.

So... it sounds like the impeller in the leg was changed the first time around - which is a moot point since it does nothing for the engine. BUT, if he knew that the impeller in the leg was not pushing water to the engine, why wasn't the engine-mounted impeller changed the first time? I'm confused again!

Novus - you've lost most of the vanes of the impeller. You need to find them. Follow the output line of the pump and disconnect as you go till you get to the heat exchanger. Hopefully you find them or you're still going to have issues - and possibly some new issues.

 

[novas_searay215ExpCrus]

Sorry, to confuse everyone. Here is the list of things I have done. Along with yes, the impeller in the transom stern drive surprised me, that I finally put it together it was not connected to the engine, that the previous owner, did install the bravo raw seawater pump and that is the only thing drawing water into the engine. So I had correcting installed the impeller into the sterndrive that was not scored because I pulled it off twice thinking I messed up because the engine was overheating after I replaced it the first time, but everything was done by the book. Next, I replaced the thermostat and backflushed the cooling system, along with running the radiator cleaner through it, along with cleaning the vents on the heat exchanger, which were pretty clean. Then I replaces the main water pump, thinking since all of that looked good it could be that because it was rusty. Then after that and the engine was still overheating. I made the major purchase of a new Dry Joint Manifold and riser system, which after pulling off the original manifold, was super necessary. It was so full of rust chunks. That installation went really well, but it was still overheating.

To find out. I had no idea that there was a raw sea water pump under the boat bringing in water, I thought the whole time the impeller was doing that alone. After discovering I made the crucial mistake of not knowing I needed the plunger thing pushing water up into the raw water pump. I just had the muffs that go over the impeller that was doing nothing. So I had been running the boat without actually having water go into the engine while testing it for overheating the entire time.

So now that I have all the correct things to make sure water is going into the engine to cool it, I ran the boat to find it is still overheating. I then pulled the raw seawater pump off the learn, that its rubber impeller is melted and shredded, the seawater pump housing is scored the damnation. So I have ordered a new housing and impeller and today I'm going to backflush the system to make sure any of those rubber chunks from the impeller are out of the cooling system. Because I don't need that to screw up all my work. Hopefully, that makes since.

 

[Lazy Daze]

Thanks for that extra explanation - that helps tremendously. It seems like you have a handle on things, now. But don't rely on backwashing alone. MAKE SURE you find all of the pieces of the impeller - they're in the somewhere!

 

[Bill Curtis]

On the missing vanes, the first place to look is in the oil / power steering cooler(s). From the discharge line on the BRAVO raw water pump, follow it around to the port side of the engine and there should be a cooler down low (it may be on the rear of the engine, too). Vanes probably stuck in there, killing your water flow and causing the overheat condition.

 

[Bill Curtis]

OK, your "guess" on what he's saying makes sense

In that case, somewhere along the line, someone added the Bravo raw water pump to his engine. Engine's aren't really a "Bravo or Alpha" - it's just a matter of bolting on the Bravo pump to the engine and adapting a new serp belt.

So... it sounds like the impeller in the leg was changed the first time around - which is a moot point since it does nothing for the engine. BUT, if he knew that the impeller in the leg was not pushing water to the engine, why wasn't the engine-mounted impeller changed the first time? I'm confused again!

Novus - you've lost most of the vanes of the impeller. You need to find them. Follow the output line of the pump and disconnect as you go till you get to the heat exchanger. Hopefully you find them or you're still going to have issues - and possibly some new issues.

Wasn't really a guess. Was a summation of the the pictures of a Bravo pump and when he stated he "needed an inboard flush thing that goes over the raw water intake" (indicating a thru hull pickup) and "because it is pumping out a tube in the top of the stern drive" (usually done when converting to thru hull pickup, the line is cut so water flow can still cool the outdrive leg).

I do understand the differences between an "Alpha" and a "Bravo" are actually just bolt on accessories.
Used "Bravo Engine" to try to simplify the confusion.

 

[Lazy Daze]

Wasn't really a guess. Was a summation of the the pictures of a Bravo pump and when he stated he "needed an inboard flush thing that goes over the raw water intake" (indicating a thru hull pickup) and "because it is pumping out a tube in the top of the stern drive" (usually done when converting to thru hull pickup, the line is cut so water flow can still cool the outdrive leg).

I do understand the differences between an "Alpha" and a "Bravo" are actually just bolt on accessories.
Used "Bravo Engine" to try to simplify the confusion.

Bill, I know you do. I was using "guess" in quotations partly because it felt like we were slowly getting more and more pieces to the puzzle (no harm meant, Novas!) and partly for sarcasm because I knew you know the difference.

 

[Bill Curtis]

Bill, I know you do. I was using "guess" in quotations partly because it felt like we were slowly getting more and more pieces to the puzzle (no harm meant, Novas!) and partly for sarcasm because I knew you know the difference.

Thanx for thee clarification