Sudden engine overheating on 5.0 MPI - 260 Sea Ray

69MachCJ

New Member
Jun 22, 2020
1
Boat Info
260 Sundancer 2002
Engines
5.0 MPI - 260HP - w/ Bravo III Drives
Hello all - Hopefully there is some help out there for us! - We have a 2002, 260 Sundancer that has just suddenly started overheating fairly quickly. It has a single engine Mercruiser5.0 Chevy MPI with a Bravo 3 I/O. I do all my own repairs & have done manifolds & risers around 3 yrs ago. Open cooling system, with a 2 yr old raw water pump I had changed out. When the overheat problem suddenly started a few days ago, I checked the raw water pump for impeller or other problems, but all looked fine. Changed out the thermostat with a new 160o stat. Went out for a test & never got to the end of our canal before temp started rising again.
Have been told by my local marina there is a valve in the thru transom that can get stuck, but repair requires engine removal! - Supposedly another option is to eliminate the raw water supply thru the outdrive & replace it with a thru-hull seacock to a strainer & on to the raw water pump. Anybody have any thoughts or help would be greatly appreciated!!--- Thanks,,, George
 
There is a water neck at the top of your transom assembly that is held on with 2 bolts. If you can't find it, follow the input hose from your sea water pump back to it. Remove the hose (mine had a quick connect there) and then the 2 bolts. You probably won't be able to look in there too easily but stick your phone down there and get a picture or two or take a quick video. If the end of the hose that's poking out from under their looks all crushed, you have Bravoitis. Not enough water is getting through. MerCruiser makes a new hose assembly that is plastic where it goes through the transom. It's supposed to prevent this from happening again. Some folks will recommend another through hull and blocking off of that fitting, but the repair isn't too bad for most mechanics. Might as well get the bellows replaced while they're there.
 

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