Boats For Sale:
Thermostat issues |
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JHadji 
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Joined: August-18-2006 Location: Pittsburgh, PA Status: Offline Points: 77 |
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 Topic: Thermostat issuesPosted: August-30-2022 at 10:29am |
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I thought I had a similar problem for the past year. My first check was if temperature is controlling. If temp goes hot and keeps going, I figured it's the impeller or thermostat.
My temperature always showed hot, but was controlling. I tried a new TS, did the kitchen stove thing, etc., but it didn't help. Turns out, it was electrical. On a hunch, I cycled the accessory & light switches on and off a few times, which made the gauges jump, but more importantly, seems to have restored the connection and I'm back in the right range. I'm not out at night much, so prob hadn't done that in a year or two. I hope you find your ghost.
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1988SkiNautique2001
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fanofccfan
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Joined: December-13-2009 Location: North Bend NE Status: Offline Points: 1796 |
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Posted: April-12-2022 at 9:27pm |
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The IR gun tells the tale. 146.7 degrees just behind the thermostat housing. Cleaned the sender hoping the crud was giving a bad reading. Nope. Going to check wires on gauge as taping the dash I could watch the needle rise. Good news I guess! Thanks for the help fellas.
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2004 196 LE Ski 1969 Marauder 19 1978 Ski
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fanofccfan
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Joined: December-13-2009 Location: North Bend NE Status: Offline Points: 1796 |
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Posted: April-12-2022 at 7:39am |
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Well-last year it seems there was also some strange cooling issues at times. (Maybe was temp gauge inaccuracy and still is). The heat does follow the yellow line referenced in Kenos picture. I will get the temp gun out to see how hot it is getting around there.
The raw water pump was removed for winter and put back on with the cam screw towards the block. It pumps at least or more than 5 gpa at 1100 rpm. I will also look around for old bits of impeller.
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2004 196 LE Ski 1969 Marauder 19 1978 Ski
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KENO
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Joined: June-06-2004 Location: United States Status: Offline Points: 11181 |
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Posted: April-12-2022 at 7:02am |
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It sounds like you/your friend took an engine that ran fine at some operating temp with a 180 degree thermostat last year, did a little winter transmission R&R, put things back together and put in a new thermostat.
The raw water pump may or may not have been touched and the cam screw (it holds the cam inside the pump housing in place) is oriented right and the pump pumps like it should from your description (It should be moving about 5 gallons/minute at 1100 ish RPM) The engine runs cool without a thermostat. Does that all sound right? The only places that have water flow in a 351w intake are shown in yellow in the picture below so checking the temperature anywhere in that area will tell you what's coming out of the engine and you can compare it to the temperature on the top of the thermostat cover.  |
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MrMcD
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Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3776 |
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Posted: April-11-2022 at 10:15pm |
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We usually see that type overheat after an impeller goes bad and the rubber pieces travel in the system and block passages. Those rubber vanes when they tear off can do lots of bad things inside but they are usually easy to clear out, it just takes time to fish them out of every hose and port. If your exhaust is cool at least the exhaust is getting good water flow.
Heat at the thermostat comes from the engine internally, there is no heat sent to it by your cool water supply so that leads back to a blocked water flow or a stuck thermostat. If below the thermostat is 140 and it is cool at the thermostat inlet you are fine. Hotter than 140 would be an issue. Mark
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fanofccfan
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Joined: December-13-2009 Location: North Bend NE Status: Offline Points: 1796 |
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Posted: April-11-2022 at 9:21pm |
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Oops. Yes the pointy thing is up! Old thermo does the same only higher temp as it’s a 180 degree. I will try the IR ext time I get over there. The exhaust was always a nice cool temp. The intake manifold was cool but the right around the thermo housing things got hot. 🤷🏻♂️
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2004 196 LE Ski 1969 Marauder 19 1978 Ski
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KENO
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Joined: June-06-2004 Location: United States Status: Offline Points: 11181 |
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Posted: April-11-2022 at 8:42pm |
You didn't answer his question, but is it safe to assume it's installed with the pointy side up?  Have you tried putting the old thermostat back in to see what you get for temperatures? Is the new one the same style as the old thermostat?
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fanofccfan
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Joined: December-13-2009 Location: North Bend NE Status: Offline Points: 1796 |
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Posted: April-11-2022 at 2:59pm |
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Standard rotation engine. drain screw is pointing towards the engine block. The raw water pumps a crazy amount of water when engine is running and hose is off the thermostat housing.
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2004 196 LE Ski 1969 Marauder 19 1978 Ski
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WakeskateNW
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Joined: December-08-2016 Location: Lake Tapps, Wa Status: Offline Points: 65 |
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Posted: April-11-2022 at 12:57pm |
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gauge accuracy might be something to explore.
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MrMcD
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Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3776 |
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Posted: April-11-2022 at 12:56pm |
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If you also installed a new raw water pump impeller at the same time it is very easy to put that pump back on backwards and get zero flow through the engine. Trust me, I did it and was lucky not to destroy my engine with an overheat. The pump bolts up perfectly in both correct and inverted positions. There is a drain screw on the pump body, it faces away from the engine or towards the engine block depending on if you have a std rotation engine or reverse rotation engine.
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cbr1000dude
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Joined: August-23-2011 Status: Offline Points: 330 |
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Posted: April-11-2022 at 11:06am |
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Installed upside down?
Weird problem. Actually, I ran my barefoot nautique big block with no thermostat for years with no ill effect. I only used the boat on hot days, why does it need a thermostat anyway? |
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fanofccfan
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Joined: December-13-2009 Location: North Bend NE Status: Offline Points: 1796 |
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Posted: April-11-2022 at 9:44am |
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I finally put together my neighbors 1989 ski and unwinterized it in the driveway with the hose in a bucket method. Great suction by raw water pump but it appears the thermostat is not opening as the temp climbed to 190 at 1100 rpm. Its a new 140 degree stat and I tested it on the stove and it opens at about 150. I tried it without a stat in the housing it stays very cool. So my question is what would cause it not to open while in the housing?
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2004 196 LE Ski 1969 Marauder 19 1978 Ski
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cbr1000dude wrote: