overheating
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=1695
Printed Date: May-14-2024 at 2:02pm
Topic: overheating
Posted By: Guests
Subject: overheating
Date Posted: May-20-2005 at 1:48am
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I have a 87 nautique that overheated when the impeller went out. I replaced the impeller and ran it at home---ran for 15 min fine. When I took it back to the lake it overheated at the boat ramp. I brought it home and took apart all hoses from the raw water pump back to the hull. All the lines were clear, the raw water pump was pulling water and the boat ran fine at home for ~15min. I then replaced the thermostat and the boat overheated at home. Both the old and new thermostat opened when they were put on the stove. Once I took out the thermostat, the boat ran fine, but cool~120-130. Could it be the circulating water pump? Any ideas?
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Replies:
Posted By: Tim D
Date Posted: May-20-2005 at 11:37am
If the blades broke off the impeller, there could be pieces stuck in the block/heads restricting water flow. That happened to mine last summer. It ran 10 degrees hotter than before, so I took it home and ran it off the garden hose without the thermostat and found several pieces of impeller coming out the exhaust. I also found one blade stuck in the bypass fitting on the intake manifold and some stuck in both exhaust manifolds. Also, take the circulating pump off, there are two holes about the size of a quarter, where water enters the block through the timing chain cover, there might be some stuck there. Mine ran about 100 degrees without the thermostat.
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Tim D
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Posted By: David F
Date Posted: May-20-2005 at 1:20pm
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Just a thought...are you putting the thermostat in upside down? Is that even possible?
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Posted By: skyhawkflyer
Date Posted: May-20-2005 at 4:03pm
Nothing is wrong, You put your pump back on upside down (and it won't circulate this way). Switch it over and mark the top.
I did this once on my 87, the pump will bolt on either way!
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Posted By: skyhawkflyer
Date Posted: May-20-2005 at 4:14pm
Let me explain, a garden hose will force feed a pump thats installed upside down (running on a trailer). But when you put the boat in the water it's unable to draw water into the pump.
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Posted By: art-p
Date Posted: May-20-2005 at 11:34pm
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I don't think the impeller pump is on wrong because when the engine is running you can feel strong suction on the intake end of the hose and I ran it in the lake last weekend for 3-4 hours. The thermostat was replaced with the copper end toward the block(the same way the old one came out). As for a blockage with a fin, if that were the case... wouldn't it overheat regardless of the thermostat being in or not? Thanks for all the input.------Art-P
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Posted By: mrese
Date Posted: May-20-2005 at 11:41pm
http://www.skidim.com/Faq.asp#RWTS
Even though there is "suction", there may not be enough. Check out the link to the FAQ section for SKIDIM.
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Posted By: jimbo
Date Posted: May-21-2005 at 1:37am
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When it overheated at the boat ramp, was it still on the trailer? Mine overheated that way one time. I don't know if it was the angle or the intakes not completely in the water.
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Posted By: Wi_Ski
Date Posted: May-23-2005 at 2:33am
I had a similar experience last spring. The boat overheated at the ramp after 10 - 15 minutes. I tried a new impeller. No change. Then, I spoke w/ a local boat mechanic who suggested checking all of the hoses leading up to the impeller for tightness. He also suggested disconnecting the hose coming off the top of the impeller, starting the engine and seeing how much water comes out. It should shoot up 3 - 4 feet as you rev the engine. Mine did not, only a foot or so. Sure enough, one of the hoses, (trans. cooler I think)was loose, just a little. After tightening, water shot out the top of the impeller just as he said it should. Cooled fine afterwards.
Just a thought, good luck.
Jeff
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Posted By: Tim D
Date Posted: May-23-2005 at 11:31am
If your boat is on the trailer and in the water, it is possible that the water can't enter the pick up screen high enough for the raw pump to prime itself.
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Tim D
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Posted By: Brian
Date Posted: May-23-2005 at 5:43pm
I had the same overheating problem this weekend on my 82. This was the first time I put the boat in this season, and my temp quickly rose far above normal operating range at the ramp. I automatically assumed I had a bad impeller. I was close to a marina so I purchased a new one and replaced it. Still the same problem. After checking the entire system I looked at my strainer, only to notice a crack on the strainer cover. I was losing vacuum pressure to pull water through. Duct tape got me through the day!!!. I now need a new strainer cover or a totally new strainer if I cant find the part. Any Ideas where I can find a replacement cover for my 82?.
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Brian
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