Posted by MW on 08/29/10 - 4:16 AM
#1
I noticed the over heat alarm was struggling to come on yesterday, it started to sound like a Gieger-counter with intermitant beeping, I headed back in and then got a steady over heat alarm *%#* (Tell tale on the engine say's YOU GOT COOL WATER), I changed out the pump last season so there should be no reason for this but, here I am. I did the standard test that my friend does..."Put your finger on the engine head and test for the "1-2-3" second count before you have to remove your finger cause it's burning" trick. I got up to number 2 and "OUCH", it's runnin hot. I removed the Thermostat at the Dock, replaced the housing, and took her out with NO stat, still some "little bit" of intermitant grumbling ( sound's like the overheat alarm want's to come on but, not really) at first from the alarm for about 10 minutes on the way out, then the alarm stopped when the head finally cooled off. I ran her hard for 20 minutes, (Fast, slow, medium speed, then back) no alarm, no overheat, cool water leaving the "Tell Tale" on the engine, head is cool to the touch... analysis is the "Thermostat". Two summer's ago the motor went into "s.l.o.w" mode from an overheat (bad stat) but no "over heat" alarm. This Saturday it had an overheat alarm but, did NOT go into "s.l.o.w." mode ?
I'm thinking- "Why didn't the "S.L.O.W" mode kick on ?
My friend think's that it was right at the alarm point (temp overheat setting)
The thermostat is 3 years old, they should be replaced every season correct ?
How come the engine takes so long to cool down (10-15 mins while running) or is that how long it takes for everything to re-set ?
Is there a computer on this engine that has to cycle to re-set everything ?
Any thought's ?
Thank's, Matt
The Plan: Replace thermostat when the dealer open's at 8:30am
6:00 PM Update:...9:30 AM Thermostat replaced, $15, Ran hard all day... Problem solved !
Edited by MW on 08/29/10 - 3:09 PM
Posted by Derwd24 on 08/29/10 - 11:32 PM
#2
Do you have any thermomelt sticks Matt? I'd change out the thermostat and run it again. If you get another overheat alarm you can use the thermomelt to confirm it's really overheated, then go from there.
Posted by joninnj on 08/30/10 - 8:33 PM
#4
Hi Matt,
I know you use her in salt... Do you flush the engine periodically? I know it is not practical when moored at a marina. I am in fresh water and very rarely change a stat. Even in salt water changing it every year is a bit much.. Have you tried to run the engine with no stat and the small stat cover off the block? This will tell you if good water getting up to the top of the engine. It should flow out of there at a good rate. If it is a very weak flow you may have a blockage somewhere... Naturally only do this tied to the dock for a minute...
One other thing... The engine will actually continue to heat up for a short period after you shut off... no water flow and engine hot... I see my temp gauge rise after I turn off the engine and leave the switch on. Only for a minute then drops. I found this interesting...
Jon
Edited by joninnj on 08/30/10 - 9:03 PM
Posted by MW on 08/31/10 - 2:42 AM
#5
Hi John,
I always flush the engine after every use (almost), I docked the boat on Saturday, then returned about an hour later to go out again, that's when all of the "FUN" started, of course I had myself convinced that for the hour the engine sat there unflushed, I had destroyed my motor. I called a friend and he said "Remove the stat and run her, if the alarm goes silent, it's the stat", I did that and the alarm went silent after a few minutes. I got down to my local dealer who's open early on "Sunday", and he said to do a continuity test on the "horn" to make sure that it's not going bad as well. The "Thermostat" was $15 and it took just a few minutes to put in. I considered myself very lucky that it was a "simple" problem and easy to repair. I'm still puzzled as to why the "S.L.O.W." mode did NOT engage ? I had "Thermostat" trouble a few years ago and the "S.L.O.W" mode engaged but, there was no warning horn.