GT 40 over heating at idle |
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scottyb1838
Newbie Joined: July-31-2017 Location: Alabama Status: Offline Points: 5 |
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Posted: July-31-2017 at 8:27pm |
My GT40 engine in over heating at idle. I've replaced the water pump,thermosat 160 degree, checked water strainer and hoses. Anybody have any idea why I'm running hot? It cools down when I'm running down the water. 97 Ski Nautique gt40 engine.
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Scott Brasher
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fgroce
Senior Member Joined: July-05-2016 Location: Georgia Status: Offline Points: 350 |
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Hi and welcome to the forum. Have you replaced the impeller? Did you use the OEM brand.? The aftermarket one's may not hold up as well. Most people recommend changing them out every one to two years. Make sure you do not see any bubbles in the strainer, that will indicate a air leak. Make sure the gasket is not missing. Hope this helps.
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FGroce
88 Ski Nautique For 28 years Now 2002 Ski Nautique |
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scottyb1838
Newbie Joined: July-31-2017 Location: Alabama Status: Offline Points: 5 |
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The water pump can as a whole assembly with a impeller. Strainer seem to be fine also put Teflon tape around to make sure no leak.
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Scott Brasher
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63 Skier
Grand Poobah Joined: October-06-2006 Location: Concord, NH Status: Offline Points: 4232 |
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Not sure I understand your water pump comment in your last post.
Running it on the trailer is a good way to see how the water flow is at idle. I suggest you use a "Timmy Tee" setup, which is ideal for running on the trailer and mimics the pull of the raw water pump when the boat is in the water. You can watch the water flow out the exhaust, see if you have decent flow at idle or only when rpm are elevated a bit. Checking flow at idle would be a good start. |
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'63 American Skier - '98 Sport Nautique
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swamp demon
Groupie Joined: March-15-2005 Location: United States Status: Offline Points: 55 |
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Is the o-ring in the strainer. How about the elbows that screw into the strainer, they may need sealed. Check inlet side of tranny cooler
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Clear Lake,Indiana
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fgroce
Senior Member Joined: July-05-2016 Location: Georgia Status: Offline Points: 350 |
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Since you replaced the entire RWP you did not put it in upside down did you. It is real easy to do.
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FGroce
88 Ski Nautique For 28 years Now 2002 Ski Nautique |
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 10653 |
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fgroce
Senior Member Joined: July-05-2016 Location: Georgia Status: Offline Points: 350 |
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Missed that later on.
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FGroce
88 Ski Nautique For 28 years Now 2002 Ski Nautique |
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MourningWood
Gold Member Joined: June-13-2014 Location: NorCal Status: Offline Points: 886 |
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Sounds like possible debris in the trans cooler or exhaust manifolds, a 'clog' that is overcome by the greater "at speed" cooling water amount.
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21109 |
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Tee is not good for troubleshooting cooling system.
Blockages will usually manifest themselves as overheats at speed, same as a failing impeller. Idle overheat is almost certainly a small air leak between rwp and hull pick up. Sounds like you missed it the first time, look at all those hoses and connections again. |
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 10653 |
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I'm kinda wondering what overheating at idle means? Are you boiling water or is it just heating up some? Numbers would be good to go by, like what it normally runs at, what it heats up to Also what led to the problem initially and what made you decide to replace the old pump In other words give a little more info |
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fgroce
Senior Member Joined: July-05-2016 Location: Georgia Status: Offline Points: 350 |
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I wonder is it really overheating or maybe a voltage issue at idling giving a false overheat?
How about using an IR temp gun and checking the temperature. |
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FGroce
88 Ski Nautique For 28 years Now 2002 Ski Nautique |
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scottyb1838
Newbie Joined: July-31-2017 Location: Alabama Status: Offline Points: 5 |
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When Idling I will get 185 +. Normally runs 160. When I pulled the RWP groves had worn into the back housing and wear plate. I thought they would've been enough water getting by to cause the overheat.
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Scott Brasher
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scottyb1838
Newbie Joined: July-31-2017 Location: Alabama Status: Offline Points: 5 |
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Thank you. Should I pull off the hose and connection and re seal each?
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Scott Brasher
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21109 |
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Pull off each hose and inspect for cracks along the length of the hose, damage from previously overtightened clamps, proper mating depth, and inspect for damage to the hard parts. Trans cooler is especially vulnerable to damage from overtightening.
Strainer bowl needs to be TIGHT (so tight that you probably won't be able to remove it without a strap wrench) and obviously the o-ring needs to be in place and in good shape. |
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