Yamaha 225 Overhgeating During Flushing

scarab30

Cadet
Joined
Jul 21, 2004
Messages
6
I recently purchased a 1994 30 ft Scarab Sport w/ twin 1994 Yamaha 225 hp saltwater series 76 degV outboards. Motors have approx 530 hrs each. Both motors generally run fine with the excption that the starboard motor has a tendency to overheat when I flush out the motor on the trailer using muffs. The motor will overheat after running for about 5 mins. I am getting a steady flow out of the telltale during flushing. The motor does not overheat when operated in the water. Any suggestions?
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: Yamaha 225 Overhgeating During Flushing

when was the last cooling system tuneup?<br /> you need to replace the water pump,t-stats and pressure valve grommet every 2 years anyway. sounds like low water pressure at an idle. check the pressure relief valve carefully,<br /> good luck and keep posting
 

sschoener

Seaman Apprentice
Joined
Jul 18, 2004
Messages
34
Re: Yamaha 225 Overhgeating During Flushing

HOW OLD ARE THE WATERPUMPS AND THERMOSTATS? EVERY TWO YEARS THEY SHOULD BE REPLACED. THE THERMOSTATS ARE VERY EASY AND NOT VERY EXPENSIVE.<br />WATERPUMP IS A BIT MORE INVOLVED - BUT I DO IT MYSELF. GOOD LUCK
 

bruce537

Cadet
Joined
Apr 23, 2004
Messages
21
Re: Yamaha 225 Overhgeating During Flushing

Hello<br />I was told to remove the plastic filter pieces in the lower end when using muffs becuase they restrict the flow too much, when using a hose and the way the muffs leak, it is NOT like having a good positive suction when the mootor is submersed. But I would also change the water pumps as the others recommend. Too many people think just becasue the tell tale is pissing, the water pump impeller is OK.......NOT TRUE. Note the force of the tell tale, then change the pump and notice the difference with new impeller and housing.<br />Bruce
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: Yamaha 225 Overhgeating During Flushing

pumps and t-stats are great<br /> you more than likely have a pressure control problem. it is another part of the cooling system that you can either maintain it or pay me to repair it.<br /> good luck and keep posting
 
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