250 Pro XS Overheating?

[my492vs]

I have something strange happening on my 250 Pro XS S/N - 18791261 with 30 hours. Air temperature was 80 degrees & the surface temp of the water was 67 degrees. I had to idle through stumps for about 20 minutes & the water temp of the motor stayed at 90 degrees. I stopped for about 15 minutes & then idled back out & the water temp was varying from 127 to 132 degrees. I stopped the motor at this point for about 3 minutes & when I hit the start button, I got a high temp warning & the temp was 176 degrees. I pulled the cowl off to check things & did not see anything out of the ordinary except the motor was hot. I let it cool for about 10 minutes & the temp cooled down enough to stop the alarm. Started the motor & the water temp stayed around 130 degrees. I then idled for about 10 minutes & shut the motor down & monitored the water temp & it began to climb. The water pressure while idling was around 3 psi, give or take a tenth or 2. Once I could get on plane @ 3300 rpm & 17.5 psi, the water temp stayed around 125 the entire time & when I shut the engine down after the long run, the water temp did not climb as before. Does this sound like I have a sticky thermostat causing the temp alarm or could this have been caused from the extended period of idling?

Thanks for the help

[basscla]

This has happened to me before. A short stop and then restart doesnt allow for the engine to cool. Infact, I believe it gets hotter before it starts to cool.

I dont think you have a problem at all, but Im sure Don will come buy and give you his thoughts

Love my 250 Pro XS

[billspence]

http://www.bbcboards.net/zerot...water

I am sure Don will be along for a true expert opinion, but here is my two cents...

This gives you some general ideas. The post is more directed at operations following a hard run but hard run or not, if you shut the motor off with the temperature rising, it will only continue to rise if you stop the flow of water (coolant) through the motor.

Watch your water temps and if the thermostats are about to open, keep the motor running until the water temp goes all the way down. You can help this by revving the motor a little while it is not in gear. Obviously, be careful with the RPMs here.

I have found that the water temp on my Smartcraft is the most important display by a long shot.

[my492vs]

Thanks for the info. After reading Don's posts about water temps, the overheating on the quick start could have been caused by my tilting the motor up before the engine cooled. The 2 things that are concerning me at this time are (1) The motor staying at 90 degress while idling & (2) the temp staying at 125 @ 3300 RPM. I bought the boat last winter & have not had it in the warm water much, so these temps may be normal, just not what I am used to after running it all winter. I keep my smartcraft guage where I can monitor the water temp & can usually tell what the thermostat is doing by the guage, but it just seemed a little strange yesterday, then when the alarm went off, I got concerned

[jxb9723]

Mine does the same thing under the same circumstances you described. 2006 225 Pro XS. Shut it off after idling for awhile and quickly restarting the overheat alarm will sound. In 2 years and 60 hours of use mine has did this twice. I really don't think its a problem unless it's consistently happening.

On your 90 degree temps. You probably had debris temporarly holding the thermostat open until it passed through the thermostat and you started seeing 130 degree temps. I've had to remove my thermostat before because a piece of sand would not pass through the thermostat and the temp would not get higher than 90 degree.

On your 125 degree run on plane. That sounds normal to me. Mine will normally run in the mid 120's on plane. My temps won't climb as much after a on plane run vs a long idle. After a long run my temps will climb to mid 140's after shut down. After a long idle my temps will climb into the mid 150's after shut down.

Trust me I understand why you are concerned. These engines are expensive and I worry about mine when there is a potential problem occuring. I really think everything is fine though.


Modified by jxb9723 at 3:24 PM 3/19/2011

[EuropeanAM]

Some very good points made above.

A couple of points to make, however:

1. Thermostats: You've definitely had a problem with them, based SOLELY on the 90 degree temps during an extended idle. If it were mine, I'd opt to pull them NOW and check them (or better yet, simply replace them).

2. Water Pump: If your water pump hasn't been replaced in the last 12 months or 100 hours (whichever occurs FIRST), I'd highly recommend doing so NOW. When chasing cooling system problems, ALWAYS, ALWAYS start at the source: The water pump. Better than 90% of all cooling system problems ORIGINATE there.

3. Restarting a warm/hot engine: Make sure that you physically trim the engine down so that the water intakes are ALL below the surface BEFORE restarting. And, IMPORTANT: Start the engine within 5 seconds of turning the key ON. If you get side-tracked, and forget to start, simply turn the key back off, and start over. It is possible for a "false" overheat alarm to occur, it the engine has drained of part of it's cooling media, and the key has been left on for 15+ seconds, an overheat warning can be triggered "immediately" upon engine startup (whereas it might have been "ignored" normally for 10 or so seconds, giving the engine time to cool down as coolant media re-filled the block).

[my492vs]

Thanks to everyone that has replied to this post. It is definitely valuable information & is greatly appreciated.
Don
I will call your place in the morning & get thermostats & gaskets ordered. Would it be wise to order the gaskets for the poppet valve & go ahead & flush it also as per your procedure in the "pinned" posts. Also, the motor is only 8 months old & has 30 hours on it. Would you still recommend replacing the water pump?
Thanks
Jim

[EuropeanAM]

Jim:

We'll be glad to assist you with all of the above.

Poppet gaskets aren't a bad idea.... since you may find that you need to flush.

Water pump: I've seen a water pump damaged on a 250 ProXS that had been in service for only ONE DAY due to a "customer error"..... so eight months and 30 hours certainly leaves some room for the "possibility".