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Joe, Marine Mechanic
Category: Boat
Satisfied Customers: 7251
Experience:  ASE, electronics, Marine mechanical and electronics, pwc, wiring, all around repair tech,
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Have two 2001 Yamaha 250 Saltwater Series OX66 outboards. The

Customer Question

Have two 2001 Yamaha 250 Saltwater Series OX66 outboards. The port motor is overheating. Mechanic is saying it's likely too much salt deposits within the water jackets, and requires the head to be removed, and the salt deposits to be cleaned. I'm an avid boater, had many boats, and am suspect towards this diagnosis. All comments are appreciated. Seems strange to me that the cooling jackets could build up enough salt from ocean water to clog the internal water jackets. These motors have less than 300 hours on them.
Submitted: 2 years ago.
Category: Boat
Expert:  Joe replied 2 years ago.
Thank you for allowing me to assist you, my name is ***** ***** I will be happy to assist you with your concern today.
This can actually occur as a problem in saltwater applications, esp when not flushed regularly/correctly.
I have seen many use an acid wash out, but we must remember any organic it may eat the metal is also aluminum which it will also attack and thus must be kept at a very min amount.
Flow and discharge can be inspected as well as checking the t-stats, pulling the head is easy enough in terms of checking for the problem if that is what is suspected through diagnosis. The other thing that can happen is the impeller coming apart and also pieces of it travel up stream and block the system, some will replace this and not remove the pieces thus still having the problem. I would pull the leg and inspect the impeller and housing. Possibly these other things have been checked and I do not have that info even by him not explaining all to you, either way those are some things to check. It also would help to know how fast it overheats and if advancing the rpms helps cool it, and does sitting at idle/no wake cause it to overheat faster or slower, etc.
Thank you!
- Joe
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