2004 F60 Overheats at Idle Speed

[Alvincat]

Hello,
I have a 2004 F60TLRC carbed 60hp 4 stroke. This spring, I replaced the thermostat and water pump as routine maintenance. Recently, I have a problem with overheating at idle speed. This will happen regularly when the engine is warmed up and idles for more than 3-4 minutes.

Just to see what would happen, I pulled the thermostat - no difference. The strainer screens are clear, and I have no problems running over about 1500 RPM.

I have done a lot of googling about this and I keep seeing references to the "poppet valve", or water pressure relief valve. I have a manual for the motor, and I do not see anything about this part, nor can I find anything that might resemble this.

Any help would be appreciated before I take it to the dealer.

Thanks!

BK

[99yam40]

Did you test the thermostat when you pulled it out to see if was working properly?

Did you put it back in?
All water cooled motors need their thermostat in place to make the water circulate properly to all parts of the motor. Without it in place there will be hot spots because of the lack of restriction of the flow through the motor.

Is this a saltwater motor? if so you may have salt/corrosion plugging inside cooling passages.

[Alvincat]

Thermostat is back in. I did not test it because it was new 3 months ago. Motor has not been in salt water. It has been in a lake with lots of growth.

[99yam40]

I have seen water pump impellers loose one or two vanes before in less that a year. May need to have a look just in case.
And while you have the lower unit off pull the stat and flush the system the best you can with a water hose

[Alvincat]

Hey thanks for your replies on this. Is there a poppet valve on this engine?

[99yam40]

I really do not know if there is one on it or not, I had a quick look at a parts break down but did not find one either.

Maybe some one that owns one or works on them more can chime in with the knowlage

[Alvincat]

I ran a vinegar solution through the flush port using an electric pump for about 30 minutes. Very little junk came out. This was done with the engine off.

Ran the engine on the muffs, overheated as before.

Dropped the lower unit, took new pump apart - everything looks good.

With the lower unit off, I hooked the garden hose up to the intake pipe - ran the motor for about 30 minutes, did NOT overheat!

Is there a high capacity impeller available for this engine? It seems like the pressure out of the water pump is not good enough - NEVER had any overheating with the old water pump!

[axolotl98]

Dont bother with overheating alarm, when u ran the engine on muffs.
You might not have enough water pressure /water flow.
Put it in a barrel full of water and check again.

[Alvincat]

Thanks. That's what I was hoping for because it has been overheating at idle in the lake. I first wanted to know if there is a better impeller before I put it back together.

[Alvincat]

Nope, took it to the lake and it overheats at idle, but not always. Only after it has run hard for several minutes, and then not every time.

Could the oil have anything to do with this? I switched to Quaker State synthetic 10W30 this spring when changed the pump. Was using Mobil1.

[Finisher]

Pretty sure there is no poppet valve in that motor. After changing the water pump did it run OK? Did you put in a water pump kit or just impeller?

[Alvincat]

Put in whole kit plus new carbon plastic housing. Motor runs ok, I just get the overheat buzzer at idle.

[Finisher]

Does that housing come with the water seal in it or did you transfer the old one over? it is the seal in the top of the water pump cover that the water tube goes into.....and did it overheat when you first put the impeller in?

[Alvincat]

It did not overheat until about the 3rd time out. The rubber seal ring is new.

[Finisher]

It sounds like it had to do with the lower unit portion of the engine. If you ran it on a garden hose and it didn't over heat with the lower off then you have eliminated the thermostat and water tube. So you said that the lake has lots of growth. I would focus on the pickups up to the pump. Could there be a restriction there. It seems your water pump isn't moving the right volume. Were these parts yamaha parts or after market? You could also try going back to your old housing to see if that makes a difference. People on here are not going to like this but you can take your thermostat out leave the cover off and start the motor and see if water comes gushing out or nothing at all. Only do that for under a min though.