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Jason
Jason, Marine Mechanic
Category: Boat
Satisfied Customers: 15613
Experience:  Degree in Marine Technology. Gas and diesel marine mechanic.
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I replaced the impeller and it does not work, it overheats.

Customer Question

i replaced the impeller and it does not work, it overheats.
JA: Sometimes things that you think will be really complicated end up being easy to fix. The Marine Mechanic I'm going to connect you with knows all the tricks and shortcuts. Tell me a bit more about what's going on so the Marine Mechanic can help you best.
Customer: my omc cobra had problems before with overheating, I had it fixed by a mechanic and only used it once and it worked, it has sat for 4 years and it started but the impeller/ water pump did not work so I replaced it and it still does not work.
JA: Sometimes boat issues seem like they'll be really complicated, but end up being easy to fix. The Marine Mechanic I'm going to connect you with knows all the tricks and shortcuts. Is there anything else the Marine Mechanic should be aware of?
Customer: I had the engine replaced prior to the overheat problems, the shop that installed it never fixed it right, until a boat mechanic finally got it working.
Submitted: 1 month ago.
Category: Boat
Customer: replied 1 month ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Customer: replied 1 month ago.
i was just clicking on things,you can send me typed response, first time user.
Expert:  Jason replied 1 month ago.

Good morning, my name is ***** ***** am I speaking with? I read what you wrote, are you running the boat in the water or on the trailer with a garden hose adaptor?

Customer: replied 1 month ago.
garden hose adapter
Expert:  Jason replied 1 month ago.

Got it. Did you replace the thermostat as well? Can you put the boat in the water and see if it pumps water when in the water?

Customer: replied 1 month ago.
I did not replace the thermostat I have a question does the engine have to get warm up before the water starts coming out of the exhaust
Expert:  Jason replied 1 month ago.

No, water should come out of the exhaust right away. The reason why I would have you put the boat in the water is some boats just will not pump water when running on the flushing muffs no matter what you do. Let me know if it pumps water with the boat in the water, or not, and we can take It from there.

Customer: replied 1 month ago.
Do I have to go to the lake or can I put in t trash can with water in it
Expert:  Jason replied 1 month ago.

You have to put it in the lake. What needs to happen is the displacement of the boat will push water up the sterndrive and to the impeller. With a garden hose or even a large bucket there is no water displacement.

Customer: replied 1 month ago.
It has had problems in the past I want to know if it's working in the lake will just overheat really quick if it's not working well
Expert:  Jason replied 1 month ago.

I'm sorry I don't quite understand your last reply. Is that a questions or is that a statement?

Customer: replied 1 month ago.
How will I know if it's working I don't want to melt the impeller or over ate the engine real bad
Expert:  Jason replied 1 month ago.

Does the boat have a working temperature gauge and a working alarm system?

Customer: replied 1 month ago.
The first part is the statement and that it is had problems in the past. no alarm system I think the temperature gauge works
Expert:  Jason replied 1 month ago.

Y​our best bet would be to get an infra red temp gun, and then scan the temps of the thermostat housing and the exhaust risers with the engine running. Both temps should not go over 160F. If the temps do get up there, then you would need to shut it down and pull the boat back out. Click this link, this is what you would want. https://www.harborfreight.com/non-contact-infrared-thermometer-with-laser-targeting-61894.html

Customer: replied 1 month ago.
The pump does not work even at the lake I have disconnected the line that feeds from the lower unit into the water pump and no. water comes out of it
Expert:  Jason replied 1 month ago.

Okay no problem. I do need to look something up. What is the year of your Cobra drive?

Customer: replied 1 month ago.
1989
Expert:  Jason replied 1 month ago.

Okay the next step is to remove the back cover from the sterndrive. Remove the water pump cover. Have a helper crank the engine over. Does the impeller spin when the engine cranks over?

Customer: replied 1 month ago.
I'm pending my son to come over and help
Customer: replied 1 month ago.
I have a question I took the impeller back off I turn the water on in the water does not come out of the two ports in the pump area of the home is the cobra should water come out of it
Customer: replied 1 month ago.
Sorry self correct change the words no water comes out of the two ports where the pump goes
Expert:  Jason replied 1 month ago.

That really depends on how much pressure your hose has. If your hose has low pressure you probably will not get any water. If you turn the hose on high, and then take the flushing muffs and squeeze them tightly by hand against the water pickups in order to minimize leakage, then you should get water up by the pump.

Customer: replied 1 month ago.
I tested it by putting the hose in the hole and water came out. None made it from the bottom up
The shaft spins. Counter clockwise
Expert:  Jason replied 1 month ago.

Okay so the impeller does spin when you crank the engine over, correct?

Customer: replied 1 month ago.
Expert:  Jason replied 1 month ago.

Got it. The impeller does have to be installed in the water pump cover in a certain direction. Click this link, is your impeller installed exactly like this? - http://forums.iboats.com/filedata/fetch?id=6964000

Customer: replied 1 month ago.
K. My. O ring. Does not want to stay in place
Expert:  Jason replied 1 month ago.

I​f the oring is falling out of place that would cause an issue as well. Are you using a new o ring or are you reusing the old o ring?

Customer: replied 1 month ago.
New
Customer: replied 1 month ago.
I have it in place with some etc for water pumps
Customer: replied 1 month ago.
R t c
Expert:  Jason replied 1 month ago.

You can use a little grease or better yet permatex aviation sealer to hold that gasket in place. Was the impeller installed as shown in the picture I sent previously or was it the other way around?

Customer: replied 1 month ago.
It was ok. I reinstalled it the sealant held it in place
Customer: replied 1 month ago.
Still no water being pumped to the engine
Expert:  Jason replied 1 month ago.

Was the impeller installed as shown in the picture I sent previously or was it the other way around?

Customer: replied 1 month ago.
it was correct
Customer: replied 1 month ago.
I just re installed it and it still doesn't work
Expert:  Jason replied 1 month ago.

If you hold those flushing muffs tight to the lower unit do you get water out of one of the holes that is under the impeller?

Customer: replied 1 month ago.
No. I tried that earlier and then I ran a hose through the hole where the impeller goes and water came out the bottom
Customer: replied 1 month ago.
Do I need to remove the lower unit could be the pick up tube on the bottom
Expert:  Jason replied 1 month ago.

If you are not getting water up to that hole then the only thing left is a clog in the outdrive. So yes the drive would need to be removed and go to a work bench to have the lower removed.

Customer: replied 1 month ago.
Can I remove it while on the boat
Expert:  Jason replied 1 month ago.

No, the drive needs to come off first before splitting the halves in two.

Customer: replied 1 month ago.
The whole drive
Customer: replied 1 month ago.
Any idea as to why my impeller is not working
Expert:  Jason replied 1 month ago.

If I am understanding everything correctly we are not getting water from the lower unit up to the hole behind the impeller, which would indicate a clog. Is that all correct or did I miss something along the way?

Customer: replied 1 month ago.
Not sure if it's a clod water will not push up The water when turned on would not come out the holes for the impeller is . The water will go down the water does not come up into the impeller holes when I had it hooked up with the water thing
Customer: replied 1 month ago.
Hello
Customer: replied 1 month ago.
Did you leave.

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