Am I overheating my 1999 Mercury 150 2.5L

[fbaxter3471]

I have a 1999 Mercury 150 V6 2.5L and I have replaced the T-Stats, Poppet Valve, Water Pump. My engine will operate on idle or at low speed at about 140-150 temp, when operating under full speed it runs 180. I have been told that the 2.5L is a hot running motor and this is normal. Also the water coming out of the pee hole is scolding hot. I have also been told again that with the 2.5L that this is normal. Ran it yesterday for about 20 minutes solid and stay at 180 until I dropped speeds down in which it came down to 145. My alarm hasnt gone off yet but my 2000 Mercury 125 doesnt have hot water out of pee hole, but that could be because I removed the T-Stats from it. Just curious if anyone else has had this issue with this particular motor.

 

[j_martin]

Re: Am I overheating my 1999 Mercury 150 2.5L

The V6 is running fine. The 125 is at risk of cold seize.

 

[fbaxter3471]

Re: Am I overheating my 1999 Mercury 150 2.5L

The motor doesnt pee nearly as good as my 125 either. The 150 is a good motor just has me with some uncertainties. The water pump is new but the stream is much lower than my 125. Could this be the cause of the t-stats or are there restrictions on this 150. I have also heard that it could be caused by a bad "EXHAUST DIVIDER". Any thoughts on this?

 

[j_martin]

Re: Am I overheating my 1999 Mercury 150 2.5L

All of the water for the tell-tale has to go through the t-stats first. In cold water, most of them piddle like a scared school boy at idle. The 125 pees well because you threw away the thermostats. It is not healthier because of it.

If you don't have a pressure gauge on the V6, put one on. If you have water pressure and the alarm isn't sounding, it's cool. The temp varies widely in normal operation. As long as it's warm enough and not boiling, it is fine.

If you have high pressure and overheat, you might have a compression leak to water jacket, or passages in and under the exhaust plate could be plugged. I doubt you have either problem.

 

[fbaxter3471]

Re: Am I overheating my 1999 Mercury 150 2.5L

Thanks you have been very imformant. When you say boiling do you mean boiling because like I said in the first thread the water is scolding meaning I couldnt hot my hand under it for more than a minute. Its very hot, but all in all the motor runs good. Its a 20ft proline sport and the 150 pushes it about 38-40mph.

 

[j_martin]

Re: Am I overheating my 1999 Mercury 150 2.5L

I mean boiling, as in making steam.

Be sure you prop it so it runs near the top of the WOT specification when lightly loaded.

 

[fbaxter3471]

Re: Am I overheating my 1999 Mercury 150 2.5L

Yes, Steam comes off the water

 

[j_martin]

Re: Am I overheating my 1999 Mercury 150 2.5L

Steam means water in a gaseous state above 212 degrees. Condensing vapors from hot water don't count.

 

[fbaxter3471]

Re: Am I overheating my 1999 Mercury 150 2.5L

You seem very knowledgable I just get so many different responses, so many people say 140-160 is the operating temp then others say 160-210 and my engine stays at 180 WOT so it leaves me a little curious.

 

[j_martin]

Re: Am I overheating my 1999 Mercury 150 2.5L

In my professional opinion, your V6 is fine. Your 125 should get t-stats put back in so it will be fine. I'm tired of arguing with you, so I'm outa here.