Overheat Alarm / Hoping problem is resolved

[Spawn Bag]

I have a 2007 226 with a Yamaha 225 on the back.

We were out trolling for coho's last weekend and the overheat alarm went off. I have gauges and the temp seemed to be within normal range however I decided to shut it down to play it safe. Started it up a couple more times for boat control however every attempt would sound the alarm. Got our lines in and started it again with increased RPM'S and the boat ran fine with no alarm. Got back to the marina and decided to bring it down to trolling speed and no more alarm. I stopped and picked up an impeller with housing and changed it sat afternoon. Took the boat out sun and no issues. The volume of water from the check hole is greater for sure. The temp also seems to be running one notch cooler on the gauge. I want to trust my temp gauge which again appeared to be within a normal range however there's no way I'm running it with the alarm going off. Problem seems to be gone but I'm still nervous and will be until I have several successful trips.

Any thoughts or even better comments.

Is there anything else you would do or check.

Thanks

PS - we did catch dinner before the alarm went off.

Jim

 

[seasick]

I have a 2007 226 with a Yamaha 225 on the back.

We were out trolling for coho's last weekend and the overheat alarm went off. I have gauges and the temp seemed to be within normal range however I decided to shut it down to play it safe. Started it up a couple more times for boat control however every attempt would sound the alarm. Got our lines in and started it again with increased RPM'S and the boat ran fine with no alarm. Got back to the marina and decided to bring it down to trolling speed and no more alarm. I stopped and picked up an impeller with housing and changed it sat afternoon. Took the boat out sun and no issues. The volume of water from the check hole is greater for sure. The temp also seems to be running one notch cooler on the gauge. I want to trust my temp gauge which again appeared to be within a normal range however there's no way I'm running it with the alarm going off. Problem seems to be gone but I'm still nervous and will be until I have several successful trips.

Any thoughts or even better comments.

Is there anything else you would do or check.

Thanks

PS - we did catch dinner before the alarm went off.

Jim

Could have been the water pump but it also could be a stuck open poppet valve. If the poppet is open, motor will overheat at low revs but not at high.

In general though if the water pump is weak, the problem will usually not occur at low revs and not loaded. It will show up at higher loads. If the poppet has issues and the water pump was weak, now the pump may be pushing more water and masking the popper issue.

You could also have a bad t-stat. It is not opening all the way when warm but does under higher water pressure.
Finally, if there is a water blockage in a cooling passage, a low water pressure condition could lead to local overheating.
I guess I haven't been a lot of help!

I find that a relatively inexpensive non contact IR thermometer can be helpful identifying bad t-stats and other cooling problems. The two heads should heat up at the same rate give or take and level off at the same temperatures. The poppet is not easy to test. If you remove it, note where everything belongs especially which direction the parts are facing

 

[beachbum]

I agree and would check things out. With that said, I have had the alarm go off when weeds are wrapped around engine or a small piece of plastic bag momentarily clogs intake and I was surprised how long it took engine to "cool down" enough for alarm to turn off. In one case, I knew it was a bunch of grass that had caused the alarm, I stopped engine, pulled floating grass away, but then had to increase RPM's so I could get enough water flowing through the engine so alarm would stop.

I think the alarms are very sensitive (a good thing) and they don't stop beeping very easily , once they activate.

I agree, a IR temp gun is valuable!!

 

[seasick]

I agree and would check things out. With that said, I have had the alarm go off when weeds are wrapped around engine or a small piece of plastic bag momentarily clogs intake and I was surprised how long it took engine to "cool down" enough for alarm to turn off. In one case, I knew it was a bunch of grass that had caused the alarm, I stopped engine, pulled floating grass away, but then had to increase RPM's so I could get enough water flowing through the engine so alarm would stop.

I think the alarms are very sensitive (a good thing) and they don't stop beeping very easily , once they activate.

I agree, a IR temp gun is valuable!!

Good point. I have experienced the plastic bag scenario and yes, it does take a while for the alarm to clear. The last time that happened, I got the alarm and shut the motor. Raising the engine exposed the bag and after removing, I lowered the motor and had no time to wait since the currents were pushing me into restricted waters. I was nervous to start the motor but in reality, that is a good thing since the pumping water will help cool off the motor quicker than just waiting with the motor off for the alarm to clear.

 

[Spawn Bag]

I have never heard of a poppet valve until this post. I see a few posts about 225's having them and other posts that disagree. Can anyone confirm that a 2007 F225TXR would indeed have one and if they should be part of regular maintenance. The rest of my serial number is 69J X 1027623. I'm also going to check the thermostat. Thanks for all your help.

 

[seasick]

I have never heard of a poppet valve until this post. I see a few posts about 225's having them and other posts that disagree. Can anyone confirm that a 2007 F225TXR would indeed have one and if they should be part of regular maintenance. The rest of my serial number is 69J X 1027623. I'm also going to check the thermostat. Thanks for all your help.

I may have spoken too soon but I am not 100% sure. I don't see the poppet on the F225. If it is there it would be called a pressure relief valve. I was speaking from experience with the 2 strokes