SoCal Jet Boats
Tech Talk => Jet Pumps => Topic started by: kev_shadow on February 11, 2016, 04:34:59 PM
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Just purchased my first jet boat.. 1979 southwind. has a 427bbc with a single 4 barrel carb. wet headers. berkely jg pump.
guy I bought it from said it was around 500 horsepower, it's an 18' boat
its completely stock.. no mods....no place diverter...
I know I want a place diverter.. question is does anyone have a similar setup?
will a long or short droop snoot help? or straight snoot?
will a ride plate help? do I have enough horsepower?
also will a rudder help me?
it has snaps that look like it has a windshield at one time does anyone know were I could find one?
all new here.. never driven. also should I get a rudder
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I run my boat without a rudder and I've heard it doesn't make that much difference anyway
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Welcome to SCJB ;D
Great looking Southwind T-deck. I don't think I've ever seen anyone use snaps to secure a windscreen, but I guess it would work. I'd recommend calling Finney's to see if they have a pattern for that hull.
www.finneys.com (http://www.finneys.com)
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How does it ride now? It does not have a shoe and ride plate now?
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Nice boat, Welcome. When I put a rudder on mine, it helped docking a little, especially when it gets windy. If I had it to do all over again, i would have spent my money on something else. :beer:
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I have not driven this boat yet... lakes are frozen here.. it does not have a shoe or ride plate... no snoot or place diverter.. just a stock 79 boat.. an older guy had it and made a trade for a snowmobile.. runs good.. loud as hell.. still need to drive it.. I just know that most boats can be improved over stock. and a plce diverter will be fun.. love to shoot a roost and show off.. just curious if anyone has a similar setup and can give me advice on my first jet..
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I have not driven this boat yet... lakes are frozen here.. it does not have a shoe or ride plate... no snoot or place diverter.. just a stock 79 boat.. an older guy had it and made a trade for a snowmobile.. runs good.. loud as hell.. still need to drive it.. I just know that most boats can be improved over stock. and a plce diverter will be fun.. love to shoot a roost and show off.. just curious if anyone has a similar setup and can give me advice on my first jet..
Save your money on the rudder. Didn't notice anything on my hallett. Def get a place diverter. Don't worry to much about shoe and ride plate right now you need to run it and see how it rides. Clean boat man have fun🤘🏼
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Post a couple pictures of the pump including the inlet area. If the pump is older and has a lot of wear that will hurt performance. Place diverted was the best investment I made.
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Welcome to the site man! If u haven't taken it out yet, I'd suggest seeing how it is when you do before upgrades and thoughts in things. It's a journey not a destination lol
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Adding performance parts to your pump can hurt performance if setup incorrectly. Plus, not all boats respond the same to pump mods like loaders, shoes, ride plates, and droops. I had a '73 Southwind 18 with only a diverter and it aired out good for what it was; a stock 455 and jacuzzi pump. All boats are different so like the other said get it on the water first and go from there. It wouldn't be a bad idea to have the pump rebuilt. A tight pump and diverter will make a big difference.
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I have a 78 t deck with a stock 460 loader shoe ride plate and just a little detail work on my a impeller no place diverted and I get over 60 mph out of it
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here are some more pics
also I am wondering what rpm I should be at...
any way to tell what impeller I have? and if there is a better one
sorry for all the "greenhorn" questions..
it is a 427 bbc with a offenhouser 360 intake with an 850 helley on top.. the guy who sold it to me says the cam has been worked...
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You don't get any more out of the box stock than that deal.
Looks like someone changed the intake fins or removed them and added forward fins.
A loader and a Place Diverter are your two biggest bang for the buck, even if the pump is worn it they will help performance.
GT
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how do I know if the pump is worn.. and whats a loader?
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so I was looking into loaders.. do these go above the grate? or do you replace the grate altogether? then the question is.. what about lake weeds getting sucked into the pump?
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so I was looking into loaders.. do these go above the grate? or do you replace the grate altogether? then the question is.. what about lake weeds getting sucked into the pump?
Loaders direct the water more evenly to the center/top of the impeller. They keep the impeller loaded with water to help prevent cavitation.
You would replace the grate with the loader.
Lake weeds... avoid 'em. ;D
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What RPM depends on a lot of things. Most similar boats would be around 5000 to 5400.
How to identify you impeller:
It will be(should be) stamped on the back of it. You'd have to take the bowl of to see it. The pump will have a metal nameplate next to where it hooks up to the driveline. It should say something like 12JG-A. This means JG pump, A impeller. But, over the years parts may have been changed.
How to know if your pump is worn:
You can take it apart and measure your clearances between the impeller and the wear ring.
Look at the impeller and check the leading edges. Are they sharp, knicked broke.
You can wait for the winter thaw and run the boat. A worn pump might seem like a slipping clutch or the engine revs to hi RPM's and the boat takes a while to get going. With a tight pump that boat should get on plane pretty quick.
Just remember, Jet boats don't have brakes and will not turn without giving it gas.
Welcome to SCJB. :thumbup:
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looks like I have a JG PUMP
A impeller.. is that good?
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Yes your pump started life as a JG-A. If the A impeller is still in there, noone knows until you pull her apart.
Here are the plus's with what you have
Clean looking boat
12JG Suction Housing
JG bowl (also called a split bowl)
My money is on it having a stock impeller and probably could use to be freshened up.
You can do one of two things.
1. Take the boat out and run it, report back to us how it runs. Even some video would be benefficial. From idle to flat foot. Does RPM syrocket? Does it climb high, then come down a bit but the boat gains speed quickly?
2. If youre bored, and like most of us, you cant leave anythign alone. Pull the transom adapter (the housing on the back of the boat) pull the bowl off and physically inspect whats in there
Me, i would go with 2. That will verify whats in there, and its shape. If everything is good, youre out a couple gaskets and some silicone. If not then you can build it now.
If you have it built, have an inducer and loader added. A diverter is a good thing to have too.
If you're really froggy. Pull the intake and have it cut for a shoe/rideplate. But thats a PIA
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looks like I have a JG PUMP
A impeller.. is that good?
:thumbup: But, if it's worn out, you could put a 1000 hp in front of it and it would still lag.
X2 to what Steve said. Taking the bowl off is pretty straight forward. Just be aware of the seal inside the bowl and that oil might come out.
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Boost here on the boards has a loader for sale :thumbup: