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 Tan Your Own Question
Tan, MerCruiser Certified Technician
Category: Boat
Satisfied Customers: 10904
Experience:  40 yrs. experience with complete engine repairs both inboard/outboard and MerCruiser Certified Technician.
Type Your Boat Question Here...
Tan is online now
A new question is answered every 9 seconds

How to trouble shoot overheating problem on a Boston whaler

Customer Question

How to trouble shoot overheating problem on a Boston whaler jet boat?with a turbo jet,johnson evinrude 115JEEO motor.
Submitted: 1 year ago.
Category: Boat
Expert:  Tan replied 1 year ago.

Hello. My name is Tan.

Ok the jet pump is your water pump so the only things that will cause over heat are, bad thermostats low speed engine operation, pressure relief valves high speed engine operation. Then finally blown head gaskets or blocked water passages.

The thermostats are located at the rear of the engine base of the power head. Here is a pic of the t-stats # ***** and pressure relief valves # ***** 2 of each. To check for water flow to the cylinder heads remove the bottom hose on the head.

We need to start with a compression test first.

The compression must be 90+ psi with no more than 15 % difference cylinders.

If compression is good replace t-stats and pressure relief valves.

The only way to check them is to remove them a physically put them in hot water. If I take the trouble to pull them out I just replace them. Then that problem is eliminated. Same goes for the pressure relief valves # ***** and seats # *****

Post back with questions and findings.

Thank you...Tan

Related Boat Questions