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79nautique 
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Joined: January-27-2004 Location: United States Status: Offline Points: 7872 |
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 Topic: overheatingPosted: April-12-2006 at 12:23pm |
If your sucking air theres a problem, there should be no air in the system. You may have a little at start up after it's been sitting on the trailer for a while but that's the only case. This type of cooling system is self purging, if it was a closed cooling system then you can trap air which isn't good and you have to get rid of the air pocket or risk damage to the engine. |
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JEFF KOSTIS
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Joined: April-19-2005 Location: United States Status: Offline Points: 817 |
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Posted: April-12-2006 at 1:17am |
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Generally speaking, I have found a intake water leak will cause the temp to rise at idle, but drop as soon as you take off and get the rpm up a bit...This is because the added rpm causes the air to water ratio to decrease. A another test is to see how much water is coming out of the system be removing a exhaust manifold hose and running it at idle and at increased rpm and comparing, and/or seeing if any air is mixed in at idle. Dont run it too long with the hose unhooked though as the manifold will get hot. Good Luck!!
Jeff... |
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jameski
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Joined: May-18-2004 Location: United States Status: Offline Points: 368 |
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Posted: April-11-2006 at 12:06pm |
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Take off all your hoses and thermostat and look for pieces of your old impellers; they are probably clogging things up.
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gregr1971
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Joined: February-15-2006 Location: United States Status: Offline Points: 67 |
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Posted: April-11-2006 at 2:56am |
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WOW!!! how the heck did i post that many times???????
hey Kevin, check the seal behind the pulley on the rwp.....??? |
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WVNautique79
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Joined: April-10-2006 Location: United States Status: Offline Points: 14 |
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Posted: April-11-2006 at 1:37am |
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Greg, the RWP is on right. It pulls water when I give it throttle.
Kevin |
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gregr1971
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Posted: April-11-2006 at 1:28am |
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sounds to me like the rwp is on backwards, done the same thing, burned up 2 impellers, was not getting water to the exhaust, turned the rwp over, no problems since. i believe the screw on the side of the sherwood faces away from the motor. just my .02.
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WVNautique79
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Posted: April-11-2006 at 1:28am |
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Thanks guys. I'm gonna try your idea as soon as I get a chance Jeff. If that doesn't work, I guess I'll rebuild my RWP.
Kevin |
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gregr1971
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Posted: April-11-2006 at 1:21am |
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sounds to me like the rwp is on backwards, done the same thing, burned up 2 impellers, was not getting water to the exhaust, turned the rwp over, no problems since. i believe the screw on the side of the sherwood faces away from the motor. just my .02.
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WVNautique79
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Posted: April-11-2006 at 1:21am |
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Thanks guys. I'm gonna try your idea as soon as I get a chance Jeff. If that doesn't work, I guess I'll rebuild my RWP.
Kevin |
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gregr1971
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Posted: April-11-2006 at 1:20am |
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sounds to me like the rwp is on backwards, done the same thing, burned up 2 impellers, was not getting water to the exhaust, turned the rwp over, no problems since. i believe the screw on the side of the sherwood faces away from the motor. just my .02.
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gregr1971
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Posted: April-11-2006 at 1:13am |
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sounds to me like the rwp is on backwards, done the same thing, burned up 2 impellers, was not getting water to the exhaust, turned the rwp over, no problems since. just my .02.
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JEFF KOSTIS
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Joined: April-19-2005 Location: United States Status: Offline Points: 817 |
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Posted: April-11-2006 at 12:45am |
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If all checks out and still a problem, you can test for a leak on the suction side by capping the main intake hose at the hull feedthru, removing and coupling another hose onto the hose that goes to the RWP intake and raise the added on hose in the air higher than the engine and fill with water. If you have a leak, you will see water come out. Suction lines are tougher to dianose as compared to the pressure side as pressure will show you where the leak is. I did this on my 302 for a similar symtom, and it ended up being a bad tranny cooler (the end cap on one end came unsoldered)
Good Luck!! Jeff... 
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79nautique
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Joined: January-27-2004 Location: United States Status: Offline Points: 7872 |
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Posted: April-10-2006 at 4:35pm |
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one of two thinks mostly is causing your problem.
1. the impeller housing is grooved or worn causing you to lose sucsion(sp), a rebuild kit or thrust plate will do the trick to fix that. 2. you have blockage or a loose fitting creating an air leak. You need to check and make sure there is nothing blocking the screen/mesh in the tranny cooler, or the hull pick-up underneath the boat. Also since you add a strainer you need to makesure it is connected properly and not sucking air somewhere. The clear bowl area should completely fill up with water and stay that way and no air bubles should be present. Make sure that the arrow on the strainer is going in the correct flow direction or towards the tranny cooler. The plumbing order should be hull pick-up, strainer, tranny cooler, RWP. regaurdless the impeller is getting cut and going out or its melting and going out. also make sure the RWP is flowing in the correct direction and pushing the water to the engine and not pull in it out of the engine. The set screw on the side of the RWP can tell you, is it towards the engine or facing away from the engine and towards the gunnel, which I believe it should, don't quite remember, I just always check it before replacing the impeller to know that I have it on the same way I took it off. |
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WVNautique79
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Joined: April-10-2006 Location: United States Status: Offline Points: 14 |
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Posted: April-10-2006 at 3:29pm |
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Hey everyone. I've been checking this place out for a while now, but just joined today. Hope you guys can help me out. Bought a 79 Nautique last summer. It started burning up impellers late last summer. It seems like it's sucking air somewhere. If I give it throttle when I start it up, it seems to get plenty of water, but if not, it doesn't. I replaced the intake hoses this spring, put in a sea strainer, and it's still having the same problems. I'm running out of ideas. Don't really want to buy a new water pump, mainly cause I don't know if that will fix it, and it's not cheap. Anyone have any ideas?
Kevin |
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JEFF KOSTIS wrote: