SoCal Jet Boats
Tech Talk => Jet Pumps => Topic started by: DOUBLEJ on May 27, 2010, 03:26:27 PM
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I just put my 79 challenger on the water for the first time. I got the boat knowing the was a problem with the motor, I had it pulled and fixed and it runs great. I took 1 trip around the lake with no problems then while idling in I noticed the motor heating up I looked in the back and no water was coming out from the thermostat outlet hose in the back of the transom. I just had it hooke up to the hose before taking it out and i had no problems with circulation. The problem has go to be with the pump or a clogged intake hose. I am waiting for it to cool done before I start diagnosing it. The question i have is my pump is a jacuzzi yj, I know they operated a lower pressure but it should put enough pressure to circulate thru the block, right ???? Someone suggested the maybe that pump needs to be ran with a water pump but that dosent sound right. While @ 3k-3500 RPM arount the lake I had no temp problems. Any ideas ????? Thanx in advance..
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Check your gate valve to make sure it's open, you'd be amazed how quickly they go to shit. Also check the water tap from the pump, look inside and make sure that there's no blockage. Good luck.
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That was the first thing I was gonna look at when it cools down. Thanx brother !!
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I checked all of that and its good, no corrosion or anything it must be in the pump itself somewhere
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this is why i check my dump while im idling out of the no wake zone ;)
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Assuming the lines are clear and valves are open as was suggested prior, heres a few things to consider , YJ's are originally equipt with a small "strainer" over the water feed inside the jet (that feeds water to the engine, this shhould be eliminated IMO (can be knocked loose easily) also one of the "harbingers" (warning signs) of significant internal jet wear on that particular model jet is engine overheating. As the jet is the "water pump for the motor lack of volume from the jet to the engine will cause it to run hot particularly at low speeds (idle etc) Good luck please call if we can help Tom
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I had a similar thing happen when the bearing in my pump blew up....the impeller got pretty tore up and clogged the cooling port with impeller debris. I'd check the pump out.
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I don't know if you fixed it yet or not, but I had the same thing happening to me and found out it was a weak hose that had a kink in it. At idle it would be kinked and not let enough water to cool the engine, under throttle it would straighten the hose allowing for the proper flow. The hose was too soft and a bit to long. Swapped them out for hard wall hoses and problem fixed. :thumbup:
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Another thing you can try is to rig the garden hose up and back flow the cooling system. that way if there is any debris it goes back out. Depending on where you boat , there could be all kinds of crap floating around in the water and can easily be stuck in the cooling system somewhere.
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Here's one for the memory bank, my boat last time out runs at right temp. when cruising,idling,or running hard, shut it down heats up fast steam coming out of the water dump. So I think I might have loaded sand into block, when I pull block drain plugs, the one on the left side of the block I can see through it, hex head iron plug rusted away. I'm thinking brass pet-cock set-up like I had on it before rebuild. :thumbup: