How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Dominick Your Own Question
Dominick
Dominick, Marine Mechanic
Category: Boat
Satisfied Customers: 1009
Experience:  25 Years Experience as Mechanic, 20 Yrs Boat Yard Owner/Mechanic, Factory Certified
14379177
Type Your Boat Question Here...
Dominick is online now
A new question is answered every 9 seconds

I have twin inboard mercruiser 5.7 inboard with closed

Customer Question

I have twin inboard mercruiser 5.7 inboard with closed cooling system...I am having a high speed overheating issue on both..high temp is within a couple of degrees on both of them..I am seeing air bubbles in my sea strainers..xould this be causing the problem..I have done a water flow test and I have have plenty of water coming out of raw water while at the dock
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 have remove all hoses and checked for any blockage..engines have new intake manifolds and new fresh water pumps..raw water impeller are also new since being put into the water.
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Marine Mechanic about your situation and then connect you two.
Submitted: 6 months ago.
Category: Boat
Expert:  Tan replied 6 months ago.

Hello. My name is Tan.

Air bubbles will cause overt. The bubbles in the water will actually cause the water to boil.

Check the seals on the sea strainers. Is the bottom of the boat clean? Any kind of growth in the pick ups will cause aeration.

The other thing that will cause over heat at high rpms are restricted risers and a scaled up heat exchanger.

Related Boat Questions