Overheating problem

B

Bob McDonough

Member
Jun 18, 2015
39
Bass River, Cape Cod
Boat Info
2002 Sea Ray Weekender / LUNA Sea 3
Engines
Mercruiser with Bravo 3 out drive
Happy 4th to all,

I am hoping someone can help me here. I have a 2002 Sea Ray Weekender powered by Mercruiser 5.0L MPI Bravo 3. When dewinterising I started it and it ran beautifully however could not get tempature to come down. It was approaching 190-200 and I shut it down. I replaced the thermostat and still have the same problem. I am trying most simple or obvious things 1st however I am not a mechanic but can figure some things out on my own. I guess I know enough to be dangerous. What should be next, water pump, impeller? And where is best web sight to find schematics?

I am hoping to get it in by the fourth and am running out of time.
Help!!!
Best regards,

Bob
 
Vapor lock? Try bleeding the system while it's running.
 
How to do what? I know there are videos however I am asking for advice on what would cause it and folks experience.
 
The hot condition could just be that when on the muffs, the water supply is just not quite enough to cool the engine. As others have said the impeller may be on the dying end of it's useful life and is contributing to the issue. Between those 2 things you could easily see higher temps than you want.
 
Bob McDonough said:
How to do what? I know there are videos however I am asking for advice on what would cause it and folks experience.
Click to expand...

In your original post you mentioned not being a mechanic but could figure some things out. I guess I assumed you were wondering how to change it. The water pump in the outdrive brings water into the engine and the circulating pump on the front of the motor moves it through and out. If you were in the water and moving at plane you would most likely see the temp come down as the movement will push water into the outdrive and motor.

You asked for a good place for a cooling water schematic. I suggested YouTube as a place that will have numerous video illustrations describing all of this as well as steps to correct it.

When you ask for help, try not to shoot the messenger. Good luck with your repair.

Shawn
 
Shawn,
I am not shooting the messenger and apologize if that is the way it appears. I am new to the sight and assumed I would get feed back with folks who had a similar experience and how they went about solving issue. Is that what this forum is for?
Again sorry but not looking to offend just help as I would for someone else.
 
Bob is there water coming from exhaust? How much? When was the impeller done?

Sent from my SAMSUNG-SM-N900A using Tapatalk
 
Bob, Do you know when the impeller was last changed? If not, I would definitely go ahead & change it. It's a straight forward task that lots of guys here on CSR can help with. Since the boat (with the B3) is on land, the task is even easier. If you are on a trailer & close enough to the water you might trailer the boat to the water keeping this post in mind...

1990-270-da-lover said:
The hot condition could just be that when on the muffs, the water supply is just not quite enough to cool the engine. As others have said the impeller may be on the dying end of it's useful life and is contributing to the issue. Between those 2 things you could easily see higher temps than you want.
Click to expand...

Good luck & keep us posted on what you find out.
 
Bob McDonough said:
Shawn,
I am not shooting the messenger and apologize if that is the way it appears. I am new to the sight and assumed I would get feed back with folks who had a similar experience and how they went about solving issue. Is that what this forum is for?
Again sorry but not looking to offend just help as I would for someone else.
Click to expand...

No apology necessary. I'm not a mechanic but I am mechanical and can fix many things but sometimes I need some help. I've discovered YouTube is a limitless source of info and how-to's. You could probably find answers to your problem as well as step-by-step instructions on how to fix it.
 
Burgundy, no water from exhaust, I am reading that you can pull the whole impeller assembly and pump to replace impeller.
 
Aweigh,

i have have owned the boat for 3 years this will be fourth. I am not sure the impeller was changed as it was being yard maintained up until this past season. I have been checking maintenance records as things were being done each year by yard and found no mention of impeller change. I have in addition found them to be let's say less than honest. So now I plan to do what I can myself as time allows.
that being said can I pull whole assembly off to replace impeller? I found a couple you tube videos showing good info on how to however in those videos engine is not in boat.

thanks for your help!
 
Here is a site that will explain everything you ever wanted to know about Mercruiser drives and how to instructions with illustrations of different pumps.
I change impellors every 200 hrs or less, just follow the instructions. I've always removed the whole assembly including bracket in one piece.

http://www.sterndrives.com/rebuild_bravo_raw_waterpump.html
 
Last edited:
Bob & Sue's link was one of my favorites when I first got my boat. Very informative.

I have done my pump & impeller and I removed the whole thing because I had to replace the pulley as well. As a side note, my pulley was plastic, which failed and was the reason for the repair. I replaced it with a metal pulley. If I were you I would replace the wear plate while you have it apart.

As another side note, When you take the old I mpeller out, hopefully it will be in one piece. Verify that all the vanes are present, or found, before you install the new one.
 
Doesn't a Bravo 3 have a engine mounted raw water pump with a seacock and thru hull?
Running it on muffs wouldn't get water to the pump.
 
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