# Yamaha 4 stroke overheating at idle



## jcasey (Oct 12, 2007)

2006 F225 - I replaced the waterpump because the stream of water coming out did not seem very strong. The stream of water after the new pump did not improve the pressure coming out afterwards. 
Now at I get an overheat alarm while at idle. No alarms while running though.
I tested the thermostats next to a brand new one in hot water and they seem to open and close as good as the new one. The Poppet valve seems fine, although I do not know how to tell if the Poppet valve goes bad. There was not any corrosion or sand inside in it.
When I replaced the water pump, I installed the whole kit, not just the impeller. Although I did not change out the key on the shaft. Would that make any difference ?


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## Ocean Master (May 20, 2008)

If the impeller is installed correctly on the old key then it's fine. Thermostats rarely go bad and you just proved that. 

Even though there was no sand or corrosion I would still change the poppet valves and grommets. But then again the poppet valves are there for high speed cooling and regulating the pressure back and forth. Usually overheating at idle is caused by the water pump. Hopefully one of the mechanics will help.

Maybe the cooling jackets need a good cleaning with vinegar??


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## Sequoiha (Sep 28, 2007)

actually if a poppett valve is stuck open it will overheat at idle, also your engine model is included in a technical service bulletin for exhaust tuner corrosion which can cause an over heat issue.. you should have it checked by a yamaha dealer, which we can do for you. call 251 987 2628 and talk to steve, let him know i said to call, have him look up your serial number for the bulletin, if it is covered then the inspection will be free and or repair will be free.


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## DOUBLE "D" & LV (Oct 2, 2007)

When you got the kit, did you get the housing as well? And, did you put the smaller o-ring in the housing before the insert went in? Sometimes, if it was a factory original housing, there is glue in them. When you replace the kit, the glue causes issues with the insert seating in.


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## jcasey (Oct 12, 2007)

Thank you guys for responding. The poppet valve does not seems stuck. I can compress the spring and it goes back to the original place. Rather than spending 60 some odd dollars for the poppet, I took the lower unit back off and removed the water pump to make sure I put everything together right. Everything looked fine. I have not had a chance to take it back out to test. 
I did replace the entire kit, not just the impeller. I was put some green grease to hold the 2 o rings in place.
Kenny, thanks for the contact info. I will call them and give them my serial number.
I do appreciate your response and was really hoping that you would be one of the people to respond. I have been a member of this forum for a long time, I just have not posted very often, although I do read a lot on this forum. I know that a lot of people on here look to you for your advise.
Thanks everyone !


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## Ocean Master (May 20, 2008)

If you're using Green Grease you already know it's the best grease made for saltwater use.


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