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Hi Ivan, my name is Jason.
Is this engine an inboard with a through hull pickup? Or is it a sterndrive using the sterndrive as a water pickup?
Does the engine run hot at all RPMS, or does it run cooler at a low rpm and hotter at a high rpm?
Got it. When was the last time the bellows, and more importantly, the water line that is in the outer transom replaced?
Did you disconnect that when the engine is overheating and at high rpm, or did you disconnect it and check water flow just at idle and when the engine is cold?
Got it. You said the water line and bellows were never replaced. How old is this engine/boat?
Got it. All Bravo sterndrives have the same problem over time. That problem is the water line in the transom assembly eventually gets soft from the passage of time. The seawater pump has 2 sides to it, it has an inlet and an outlet. When you are running, the inlet side is always under a vacuum. The higher the engine RPM is, the higher the vacuum. When the water line gets old, it gets soft, and it eventually starts to suck itself flat at higher rpms, this causes a water restriction and causes the engine to starve for cooling water at higher engine RPM. In the shop we call this Bravoitis (similar to tonsillitis, except what you have is a sick bravo)
I am here, I am just trying to type you up a complete answer. I am not the fastest typer so I do apologize for any wait.
Click this link to pull up a new web page, this will help explain what is going on with your engine - http://www.amarket.com/BRAVOitis.htm
If you look at that page you can see what happens, the water line simply gets soft over time. Engine hours do not matter here, as rubber dry rots with the passage of time. Even if it was brand new and had zero hours on it, that water line would still become soft over time. On Mercruiser engines the bellows should be changed every 5 years, it is standard operating procedure to change that water line at the same time. What needs to happen on your boat is that water line needs to be changed. The best and most cost effective way to do this is to change the water line and bellows at the same time. Once it's done then you don't have to worry about it for another 5 years. This is a normal maintanence item, and part of normal wear and tear. Job wise, it's roughly 800 bucks total in parts and labor as long as there are no surprises. It's roughly 350 dollars in parts and the rest is labor. The job takes 5 to 6 hours to complete.
I don't know how you want to leave this but that is where you stand on your end and what needs to be done. I think that should do it but I work for tips so I do want to make sure you are happy with my service before you go. If you had a further question on the issue by all means feel free to ask. If not, Just in case you do not understand the way the website works (and some folks do not). You do have to put forth a positive rating in order for it to credit me for helping you. When ratings are not done, the website simply keeps your deposit and they will not credit me. The ratings box is located at the top of the screen. To rate, you must select the star you wish and also confirm it. Please let me know if you run into any problems or errors when trying to do it. If you do have a problem, or if you can not see the ratings box which is at the top of the screen. Please reply back "I rate Jason's service _______" and fill in the blank.
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No, a head gasket would not cause this problem.
The problem is going to be that water line. Did you have a chance to look at the link I sent you?
Did you have any further questions for me on the issue?
Okay good. Did you have any further questions for me on the issue?
The sterndrive has to be removed, but not the engine.
Also, to add to this, I know that you probably think that there is something "really wrong" with your engine. However, this problem is really just normal maintenance. This isn't something odd or out of the ordinary or some mystery. This is pretty normal, and a common complaint.
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Thanks again and good luck!
Was there anything else?
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Hi Ivan, Just checking in. No rating has been put through for me yet, did you still have questions on the issue? Jason
How did you end up making out?