Overheat alarm on startup again. Why does it do this?

[06champ198]

I have had this problem on and off the last year or two. Water pump has been replaced with good pressure. It is the same symptom everytime. This time I was fishing in the same cove as take off. I started the engine and idled over to drop my partner off. About 5 minutes or less to the ramp. Dropped partner off. Idiled out of everyones way and shut down engine. I put all my rods up and loose stuff. Maybe took about 10 minutes. It was my turn to load and I started the boat. Instant overheat alarm. I have been down this road before. I put boat in gear and start to move and overheat goes away. I shut if off again and restart. No alarm. It seems to be getting heat soaked. Do I have a problem Ran great all day with no issues. This just happens from time to time.

2006 225 PRO XS

[rangerguy]

Heat Soak, your motor heat goes up when you shut the motor off and flow of water stops. So when you start it up again and before the water gets up to the motor again, your alarm senses the heat in the motor and alarms. I wouldn't worry about it.

[gambler4]

don will be along shortly but there was a problem with a leaking gasket and some steam or vapor when you shut the motor down would trigger an overheat. once you started it up it would exhust the steam and your overheat would go away

[EuropeanAM]

First of all- and most important: DO YOU HAVE A SMARTCRAFT INSTRUMENT? If so, which one? Very important to know FOR SURE that the alarm you received is INDEED and overheat- and WHAT TYPE of overheat (compressor or engine).

We so see overheat alarms under these types of circumstances, sometimes, with no actual mechanical issues. Usual causes (all of which result from heat soak) are:

1. Engine hot, trimmed high enough to open one or two of the side intakes- water drains out of block, allowing engine to "perk" with little or no water present.

AND/OR

2. Key is turned on, and engine is not "running within 6 seconds". If you turn the key on, start the engine. If for some reason you get side-tracked, turn the key off, then back on and restart. Once the "6-second mark" expires, if the engine is "heat-soaked", and you start it, the PCM will trigger a prompt overheat alarm. On the flip side, if you start the engine right away, the PCM will begin to see water pressure building, and "watch" temps falling, which may "prevent" the overheat warning buzzer.

#2 commonly happens when you see a fish jump.... or realize you forgot to tie down a rod.... or perhaps a buddy idles by and you take a minute to discuss your favorite spot, etc.

Anything familiar here?

[06champ198]

No smartcraft. Will be ordering one from one probably over the winter for install. I will verify these things however I know the key was off and the boat set for about 5 to 10 minutes prior to restart. Matter of fact I have only noticed after I have idled for a period of time then shut the boat down for a few minutes and restart. Then it does it. The motor was trimmed all the way down. Sounds like I need to get with you and get the Smart craft ordered. When it was in for service last September they noted a port side overheat alarm twice. I kept track via notes and it matched the number of times I heard the alarm.

Thanks for everyones help. I will be in touch about the Smartcraft.

[sethv]

06Champ- Mine does the same thing. Trimed down - if I shut it off for 1 - 5 minutes or so (like when I am waiting for my trailer to load after i drop my partner off) it will go off on restart.

On my smartcraft the temp might be in the 170 range. It quickly falls within a few seconds after I start up and horn goes quiet. Horn goes off and the little bell symbol flashes as soon as the key is "on".

Engine always runs 129 - 131 under normal opperation.

Seth

[06champ198]

Thanks Seth. Sounds like I dont have an issue then.

[jxb9723]

06champ198.

IM sent.

[jxb9723]

I have a 2006 Pro XS I had the same problem twice.I have a smartcraft gauge and here is my observation.The thermostats control the temp of the engine.When open the temp drops down to 118 degrees.When closed the temps can reach 143.Temps will flucuate up and down until the engine has stabilized around 132.I've noticed that when I shut the engine off and the thermostats are open no overheat on startup.If I shut it off when the thermostats are closed near 143 heat soak causes overheat on startup.I've found it to be a timming thing.If I pay attention to my smartcraft I can avoid it. This is why the problem is so "intermittent" and "occasionally" happens. There is a very small window right before the thermostat opens and cools the temps down that if the motor is shut off at the wrong time it can cause this problem. When the alarm is present the temp on the smartcraft is in the 170-180 degree range. As soon as water starts pumping temps drop to 130 imediatly. I don't think it is a mechanical problem.A friend has a 250 proxs and experience the same problem.

On my previous 200 and 225 standard optimax this never happened but the temps ran slightly lower on those engines. usually in the 115-138 range and stabilizing around 128. Maybe this is only a problem on the Pro XS models since they are true high performance engine not intended for long periods of idling.



Modified by jxb9723 at 2:48 PM 4/18/2010


Modified by jxb9723 at 3:09 PM 4/18/2010

[EuropeanAM]

You might benefit from removing and checking your thermostats... AND your poppet valve.

I suspect that the plastic poppet is too tight in the rubber grommet, and is not closing completely after you come off plane. This can result in lowered water pressures, and elevated idle speed temps "intermittently" (as well as overheats on startup when the engine is already warm).