SoCal Jet Boats
Tech Talk => Jet Pumps => Topic started by: dustin on June 01, 2009, 08:57:34 PM
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I'm new to the forum. Earlier I asked about a slit bowl for my pump, but after reading some post I have alot more questions for you all. First off I have a 1977 sundance 18'. It has a 454 with right around 450 horse. The pump is a bearkley 12 jc with a diverter. My problem is that when you are taking off if you just mash the throttle it just sitts there and cavate's. I do alot of skiing, wakboarding so this makes it hard. Plus I'm getting beat out of the hole by a out board... I don't have a speedo in the boat, but were guessing it goes right around 66 mph, just from racing a few with speedos. I would not only like to fix the cavatation problem but would like to get some more speed out of it, Also some more roost. With the diverter all the way up the only time you really get roost is if you floor it. So I'm wondering if any one know's a good set up for my hull. I don't really want to hasle with a ride plate, does the droop snoot that place diverter makes with the ride plate in it work ok? Hope I can get this figured out befor my buddy with the outboard beats me any more. :banghead:
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Come on guys, hes getting beat out of the hole by an OB :o :o. We just cant have that !! Give him some ideas.
IMO, If its cavitating that bad out of the hole, I'd say it time for a rebuild or there's damage to the impeller. Whats your RPM at that 66 mph ? You need to crawl under the boat and look up into the intake, make sure there's nothing up there that shouldn't be there, 200' of fishing line wrapped around the shaft (sabotage from the OB), ski ropes (sabotage from the wake boats), etc . While your under there look at the front of the impeller for damage (nics, chips, missing pieces, etc). If everything looks perfect in there you might need a rebuild, and next time don't run the boat out of the water unless you unhook the pump from the motor. ;)
BTW, Welcome to the site. ;D
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dustin, you need one of these...........
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;)
Do like papa proppy says and let us know what you find (like the next door neighbors cat in the pump or something :P )
GT
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Well thats another problem I have. I don't know what rpm I'm running. We rebuilt the motor a while back, and put a msd pro billet dis on it and now my tach won't work right. I need to get one that will work with that dis. I guess the stock hardin tach won't work. I also have done all those checks and every thing looks good. I definently let out of it when it cavatates...
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If you don't want to change the tach, MSD makes a tach adapt unit that will allow you to run your non compatible tach. They make two different ones depending on what trigger you are using for the MSD/tach. They run about $50.00.
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Wouldn't an MSD 6AL unit also work with his tach and Dizzy? I'm thinking it would, and might solve more problems than that.
Ray
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Thats cool if the 6 al box will fix my tach problem I was already looking to get the box.
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Wouldn't an MSD 6AL unit also work with his tach and Dizzy? I'm thinking it would, and might solve more problems than that.
Ray
I was assuming (no comments) that he already had an MSD 6 box on it. If you're having problems with the tach with a "ready to run" distributor there is something else causing it (not the MSD dist).
The multiple spark of the 6a/6al is what disrupts many tachs available. That is the reason for the Tach Adapt unit to correct the signal.
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Thats cool if the 6 al box will fix my tach problem I was already looking to get the box.
There's more than one version of the Pro-Billet distributor that has a module inside. Which one are you running? (part #?). One appears to have a dedicated tach lead. The other is the HEI version. If HEI, you will likely need the adapter since HEI has an odd tach output signal.
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I don't have th eboat right here to look at the dis, but it's not the HEI I know that. With that said I realize knowing your engine's rpm's is critical in your impeller choice. I am more worred about setting the pump up so it is not cavatating. I will more then likley get a new tach along with the 6 al box.
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I've not played much with the MSD unit, Mine are Mallory (Including the new one I just bought for "Blue My Wad"), and it has a dedicated tach line that's supposed to work with any electrical tach. (Does not hook up to the negative coil terminal)
Just thinking out loud.
Ray