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Hey guys, I've got a good one for you. water pumps fine at 3000 rpm, when I get to 5000 rpm it quits pumping. nothing is pluged anywhere -10 line in and -10 line out. I found that it doesn't matter if im at the lake or on the trailer out of a bucket. again nothing pluged up or blockage. I know those pumps eat impellars, but do they just not pump enough water at high rpms.
Bill
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Have heard of and experienced this problem before. For some reason,over time, the cap on the neovane pumps become too oval thus losing some of thier pumping capacity. I have put them in a vice and "squeezed some round " back into them and brought the pump back to life. If this doesn't work check out the cam driven water pump in the Rex Marine catolog . Can't remember what they are worth but they work great. Good luck
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sgdiv7, I would first change the impeller. It sounds to me like the impeller lost some of its tension. The blades are flattening out at the higher rpm.
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I'm with 058 on this one,the impeller blades are permanently pushed on one side ,because of the excentric position of the outer housing.It's a good thing to periodically change the position while the boat stored,or even better,remove the impeller during winter layup.
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hey guys, the impellar was just changed a month ago and i pulled it apart and one of the blades was missing so I put a new one in and it did the exact same thing. I could only test it running on the trailer and water started falling off after 4000 rpm and at 5000 there was none. what pumps do you guys run? this thing has me baffled. I can't go fast when the boat cops are around because boat is to loud and I don't want to hurt $10,000 worth of engine.
Bill
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So when you changed your inpeller one of the blades was missing. Did you get it out? If not it is in one of you hoses. They seem to get stuck in the fittings most of the time. This could cause enough restriction at higher rpm. It happend to me before. Everything was great at low rpm but would not flow at high rpm. I found impeller parts in the fittings.
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Magniflow, the are a little expensive but I fell they are a better pump. I've got a spare neovane if you need.
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hey guys, the answer to daves Question is the vane was just folded in half and was still attached to the impellar. I did some more since my last post, I ran the engine and did a free flow test on the pump (but first had to do a little inventive pluming to keep the engine from over heating)and it passed the test,it increased flow from 3000 rpm all the way to 6000 rpm. Now I belive that when the pump reaches psi. the vanes lay over and quit pumping. What I need is some ideas on how to make some kind of high psi. bypass off of the outlet of the pump.
Bill
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sgdiv7, you should never run a neovane pump for more then 20 seconds without water.I have this pump in my V-drive boat and it works great.As superdave mentioned ,just one blade gets stuck in your hoses will cause problems.I think you have some pieces left in your system from the previous impeller.Do you remember missing some from it when you replaced it?
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One other thing to look for is a flapper in one of your hoses. Sometimes the rubber can come loose (by the fittings most of the time) inside the hose. It is not a problem at low flows but as the flow increases the rubber flap will move out to restrict the flow. This has also happend to me on an old hose that I put a new fitting on. I lost some sleep trying to figuer that one out! It was like a check valve, the hose would flow one direction fine but no very well the other direction. I used compressed air to blow out all my hoses and found that one would only flow one way. You might want to try that too.