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2003 BF225A3XA Overheat Alarm at idle

mshoultz66

mshoultz66

New member
After a few minutes my 2003 BF225A3XA will sound a steady alarm. The overheat/temp light is on, the green oil pressure light is on, the check engine light is off, the alternator light is off. The pee stream is lukewarm. After 30 seconds the motor will turn off. I shunted the service plug and didn't get any codes from the ECM. The engine was fine at the end of the season (December). My marina changed the lower unit fluid, fogged the motor, and stabilized the fuel. I just changed the oil/filter before starting it up. Thoughts?



[video]https://photos.app.goo.gl/wA38nQYQh37a4NBT9[/video]
 
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mshoultz66 said:
After a few minutes my 2003 BF225A3XA will sound a steady alarm. The overheat/temp light is on, the green oil pressure light is on, the check engine light is off, the alternator light is off. The pee stream is lukewarm. After 30 seconds the motor will turn off. I shunted the service plug and didn't get any codes from the ECM. The engine was fine at the end of the season (December). My marina changed the lower unit fluid, fogged the motor, and stabilized the fuel. I just changed the oil/filter before starting it up. Thoughts?



[video]https://photos.app.goo.gl/wA38nQYQh37a4NBT9[/video]
Click to expand...

Ok based on other readings from this forum, I checked the temperature of the water jacket when the alarm sounded. Port was 101 F. Starboard was 181 F. I'm assuming that indicates a bad thermostat on the starboard side? I think I read the thermostat is supposed to be fully open at 157 F. Not sure how high the operating temperature can be before the alarm is set. Do you all agree that this is probably the thermostat on the starboard side? Am I missing something? Thanks.
 
Pull both t-stats and test in a pan of heated water. Should start opening at about 130 F and be fully open at 160 F. Fully open is only 3 mm. If in doubt, replace them. They're cheap. When you pull the t-stats, check for corrosion and even a possible leak under the seat. Unfortunately, flushing water hardly makes it that high into the cooling passages unless you use a lot of pressure.

Also, Honda started installing a collar/spacer on the port t-stat. See part 28 at:
https://www.boats.net/catalog/honda...la-2007-and-later/exhaust-manifold-thermostat

Note that is not present on the 2003:
https://www.boats.net/catalog/honda...p/bf225a3-la-2003/exhaust-manifold-thermostat
 
That port t-stat may have failed as well, in the wide open position.

In any case, if you're going to replace one, I would do both.
 
All thanks for the feedback. Pulled the t-stats and found port was indeed stuck open. Performed t-stat test and found starboard failed to open at all. Found no corrosion or leaks under the seat. Running on square muffs with water delivery to both sides.

Will replace both. I have ordered two new t-states and o-rings.

CHawk_man are you suggesting I install the collar/spacer as a mod even though the 2003 didn't have it?
 
Glad you found the issue.

Yes, I would recommend adding the collar. And note that you will also need three new (longer) bolts. PN 90146-zwy-000.
 
Square muffs are the worst, Cheap round ones work the best....

You cannot diagnose an overheat issue on a large outboard with the garden hose. Even with good water pressure and all parts of the cooling system working 100% it will set off the alarm.... Sorry.

If you have to do it on the trailer, get a garbage can or Antifreeze drum.....
 
Docksidemarineservices said:
Square muffs are the worst, Cheap round ones work the best....

You cannot diagnose an overheat issue on a large outboard with the garden hose. Even with good water pressure and all parts of the cooling system working 100% it will set off the alarm.... Sorry.

If you have to do it on the trailer, get a garbage can or Antifreeze drum.....
Click to expand...

This.... my Honda 225 will overheat with the more expensive dual feed muffs, the cheap round eared ones with the metal wire and single feed from west marine work fine. The cheap ones fit tighter around the intake ports, pretty rare when anything that's the cheapest works the best.
 
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I appreciate the advice and feedback. All I can say is I've run the square muffs many times before and never had an overheat problem. I would think that the amount of water pressure and the diameter of the hose would have a larger impact.YMMV. I do agree that the best way to be sure is to have the boat and motor in the water. It was also fairly easy to pull the thermostats and test them by suspending in a pan of heated water and measure the temperature when they open. In this case I had one that did not open and one that was stuck open when I removed it.
 
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