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Ask Dominick Your Own Question
Dominick, Marine Mechanic
Category: Boat
Satisfied Customers: 1009
Experience:  25 Years Experience as Mechanic, 20 Yrs Boat Yard Owner/Mechanic, Factory Certified
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I have a 2007 496 Ho mercruiser stern drive, while running

Customer Question

I have a 2007 496 Ho mercruiser stern drive, while running the boat at high rpm she went into guardian mode. I had to drive back to the dock at 1000 rpm to keep the alarm off. I took the boat out of the water and removed drive. I tried to flush transom hose with water pressure. had to remove transom hose flange and found barnacles in hose. removed barnacles and put back together. I flushed all hoses and steering cooler.
Installed new water pump. I put back in water still going into guardian mode at 1100 rpm engine running warmer than usual but not over heating.
Yesterday I tried the bucket test and I got 5 gallons in 30 seconds at 1000rpm with a clear hose off my power steering cooler. I do have a 30 lb pressure guage rigged off a brass t at my water pressure sensor. im not reading a whole lot of pressure, o at idle and 3 at 2200 rpm.
MY Question, is can i have some barnacles blow past the 2 coolers and get into my port side manifold and extension causing blockage.
Can a blockage going out cause aow water pressure.
Submitted: 3 months ago.
Category: Boat
Expert:  Jason replied 3 months ago.

Hi Steve, Jason here.

Do you have a Bravo sterndrive?

Customer: replied 3 months ago.
Expert:  Jason replied 3 months ago.

Got it. When was the last time the bellows were changed?

Customer: replied 3 months ago.
Just changed bearing, bellows, and transom hose.
Expert:  Jason replied 3 months ago.

Okay then at this point you would need to have the engine hooked up to a scan tool in order to figure out why it's going into guardian mode.

Customer: replied 3 months ago.
ok, can i buy a scan tool. which one would i need.
Customer: replied 3 months ago.
when i disconnect water pressure sensor i get 2 beeps per min. engie will run above 1100 rpm
Customer: replied 3 months ago.
Jason, I have someone lending me a scan tool on Saturday.
Expert:  Jason replied 3 months ago.

Okay let me know what you find.

Customer: replied 3 months ago.
Expert:  Jason replied 3 months ago.


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