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sgdiv7
09-04-2001, 01:56 PM
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

restofreak
09-04-2001, 05:27 PM
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

058
09-04-2001, 07:42 PM
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.

spectras only
09-04-2001, 08:09 PM
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.

sgdiv7
09-05-2001, 05:31 AM
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

superdave013
09-05-2001, 06:20 AM
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.

schiada96
09-05-2001, 07:09 AM
Magniflow, the are a little expensive but I fell they are a better pump. I've got a spare neovane if you need.

sgdiv7
09-05-2001, 09:55 AM
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

spectras only
09-05-2001, 10:37 AM
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?

superdave013
09-05-2001, 01:24 PM
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.

Brewer
09-06-2001, 08:01 AM
I had a problem with the pump constantly "eating" impellers, along with overheating at speed. After several frustrating sessions, I found that polishing the inside of the cover restored the efficiency of the pump. The inside of the cover didn't even look bad, but apparently it was enough to disrupt flow. I used 220 grit sandpaper, working my way up to 600. Good luck

sgdiv7
09-06-2001, 07:16 PM
Hey guys,
I took all lines off and checked for being pluged or flaps in hoses, couldn't find nothing. I hooked up a psi. guage to check water psi. and I found that it was 3lbs at idle and 15 lbs. 6000 rpm. Does this sound about right for 2 -8 lines one going to the headers and one exiting the boat? no thermostat in the system.
I have another question, is it possible at W.O.T. /460 CI. bbc. with 8 lbs of boost that there is not time enough for the water to turn to steam before it comes out of the headers. the engine does not over heat. Temp. always stays at 180 deg. people watching tell me that there is no water comming out of the headers when I have my foot to the floor. when I am at a cruise speed all kinds of steam. Am I just Chasing a ghost here?
Bill

sgdiv7
09-10-2001, 12:14 PM
Thank you guys for all your help. I went to the lake this weekend talked with fellow v-drive boaters all running blown BBC. come to find out that all there boats do the exact same thing as mine. The problem is need to inject more water, the water lines will not flow enough water.
Hey Superdave, you were right big restriction.
Again guys thanks for all your help.
I have a good excuse to buy new headers now huh,
Bill

superdave013
09-10-2001, 01:39 PM
Hey glad to help. I would not inject more water into your headers though. Who cares if they are not steaming at WOT. Your not doing 100 mph passes in front of the Ranger anyway. You are getting some water in them. I myself hate water injection. I have f--ked up more than one set of exhaust vlaves because if it. I was running dry headers with mufflers. And when I did run injection, I injected it in the collector as close to the end as i could. I even installed a tube that was bent 90 deg so it was facing the end of the collector. It still got in the heads!! Big cams and water injection did not work good for me.

Gary
09-18-2001, 06:55 PM
10-4 on that one Super D. Stuffing more water in the engine is NOT the answer. If your water temp is not exceeding 180, I wouldn't be concerned. The minute that block is not getting enough water due to a plugged line from a vane for example, the temp will go to 240 or more in a matter of a minute or so. You are getting adequate cooling as it stands IMO.

DANS66STEVENS
09-22-2001, 12:32 PM
I HAVE USED A CAMPER ELECTRIC WATER PUMP FOR THREE YEARS. I HAVE RUN IT DRY. I HAVE DONE STUFF TO IT THAT IM SURE YOU SHOULDN'T AND IT STILL WORKS LIKE NEW. I WAS TOLD ONCE BY A GUY IT WOULD NEVER WORK.IT IS KINDA NOISY.JUST THOUGHT ID THROW IN MY 2 CENTS.......