Jet Drive on Argo

[Coop]

Yup....Thats my " Mystery 6x6". It has a Berkleley 6JA pump in it. In that video, I'm running the pump about 3000 rpm, which is about half it's recommended max rpm. It was propelling me with no problem. I'll be interested in seeing how you couple the engine to the pump, that is where I am at right now with my drive, I want to get rid of the mechanical coupling and come up with some kind of remotely activated clutch, either electric or air,( like Chris Davidson has done with his homemade 8x8). Cool project....

Coop

[Pontello8x8]

Hi Coop, I will transmit power to the jetdrive with a cardon from the engine, disconnect it with an eletctric clucth.
What is the speed of your 6x6 in the water with this pump?
Thanks

Luca

[Shawn H]

Check out what these guys are doing at
MOKAI Manufacturing, Inc.
You may pick up some ides for your project.
And this one in popular science
Jet Kayak | Popular Science

[Coop]

Luca...I don't know exactly how fast it will go, that video was my first and only time I floated it, the engine quit 100 feet from shore due to a bad fuel pump, I spent most of the time " McGivering " it to get the engine re-started to get back to land. But i can tell you that in that vid I was running the engine around 2000 rpm, which is about half throttle, so it will probably move along at a pretty good rate. That was with the transmission in neutral, so all the propulsion was with just the pump, the wheels weren't turning.

The problem with my set-up is that the pump is driven by a shaft off the front of the engine, there is a coupling welded to my crankshaft pulley, that has a shaft connected to it. the other end of that shaft is supported by a bearing, in the middle of that shaft there is a sprocket/chain that drops down to the pump to drive it. At the pump, there is a goofy gearbox that has a sliding coupling on it to engage/disengage the pump. That means to engage/disengage the pump you have to stop the engine, reach down into the hull, loosen a set screw, slide the coupling back and forth...a PITA. So I want to fab up a clutch of some type, air or electric that I can mount on the engine shaft and run a chain or cogged belt directly to the pump shaft, problem with that is that I can't remove the exhisting gearbox from the pump and run the pump direct, the pump gearbox reverses the rotation of the pump in relation to the input. Gotta be a way, just haven't fiquired one out yet....

Coop

[Pontello8x8]

I've got a question...
what's happen to the main shaft's bearings of the transmission gear if the engine run at full speed but with the gear in neutral? is possible that the oil stay in the bottom and not lubrificate the bearings?
Thanks

Luca

[Coop]

Luca....The transmission in my machine is a VW Beetle transaxle. No harm will be done by running the engine and not having the transmission in gear. The main shaft of the transmission will be turning, just not driving the output gears, the oil will still be slung around by the mainshaft, getting proper lubrication to all the bearings and gears. Just like letting your car run when it is out of gear and you're not moving.

Coop

[Pontello8x8]

Thanks Coop for your answer... but I have an avenger... with his transmission ... the question is about my transmission. :-D

Luca....The transmission in my machine is a VW Beetle transaxle. No harm will be done by running the engine and not having the transmission in gear. The main shaft of the transmission will be turning, just not driving the output gears, the oil will still be slung around by the mainshaft, getting proper lubrication to all the bearings and gears. Just like letting your car run when it is out of gear and you're not moving.

Coop

[Pontello8x8]

Ok... I have verified that there's not lubrification to the main upper shaft's bearings if you run the engine at top speed in neutral. I will solve this problem with a electro mechanical pump.

[mitchamus]

one idea may be to shoe horn in a small gearbox from a tractor slasher, or small PTO mower

that should be able to more than handle any load you throw at it.

I think a v-belt pulley attached to the cutter side and your drive shaft hooked to the PTO side might work.

finding one small enough to fit in the engine bay may be a problem.

[chris davison]

I like it especially the reversing clamshell I'm going to try to copy.

[chris davison]

Hey guys I have already solved some of the problems your talking about. my pump sucks directly from the bottom of the machine and I built the hull to accept the pump I had already bought, I have a s/s screen with 1/2" square holes ready to go into the intake, there is nothing hanging below the surface of the bottom of hull except tires,I draw 7 inches of water and the pump is totally submerged The pump turns backwards as to the crank so I put a chain on to reverse the direction of drive until I verify I have the right ratios I want to use all 53 hp to get to 3600rpm. This is all engauged by an air clutch with a switch in the dash. No two stroke gas, no prop hanging below the hull, no stopping the motor to engauge the shaft, no outboard hanging around and banging, no need to get out and raise it up or figure out steering for it, no second engine for it. just drive into the water shift to neutral and flick a switch and give her gas. Most of everything I found on ebay. I use air clutches at work the Nissan brand they make one for a 1" shaft thats good for 50 ft lbs torq.

[Coop]

Chris....A couple of questions...I am doing something simular with a jet drive on my machine and I am curious how you got the pump to turn backwards from the crankshaft rotation? I have that same problem, I've decided to run my pump with a hydraulic motor which I can run either direction. I will be running a chain from the motor to pump and I will be playing around with the ratios too. Are you sure the pump will be running fast enough at 3600 RPM? From what I've read, pump speed should be around 6000 RPM, I know when I had mine in the water with the old drive, it was turning around 7500 RPM. Maybe I'm not comparing apples to apples, your pump might be bigger, mine is a Berleley 6JA, off a 60's SkiDoo.

Coop

[foxvalley]

Hey, If you guys haven't seen this yet,you should check this out. Google,Hydratrek or argosalesAU. The hydratrek xt66 isn't jet propelled, but is doing what I think you want with props. Might get some cool ideas.

[chris davison]

Coop my pump is off a 90s something seadoo and has a racing impeller that gets more water per rev. once I find the right ratio ( fastest I can spin it with 53 hp) I will copy that ratio with a belt sys. ( double sided cog belt 1.5" wide ) Chains were not meant to run at that speed but temp. is ok for testing. Reversing direction is easy with chains or belts on mine there is a sprocket on the pump shaft and directly above that is the clutch sprocket, The chain is wraped 180 degrees around the pump shaft sprocket then goes up to two idlers on each side above the clutch sprocket then down under the clutch sprocket there are pics of this setup in the threads of custom volkswagon powered 8x8 with seadoo pump. going hydraulics on your pump will work good if all is sized correctly your dcv should have a motor spool so when shifting from forward to neutral your pump shaft will coast to a stop instead of stopping instantly because of blocked ports in the dcv. As yet I have no idea how a pump will work in reverse but if your intake gets clogged it sure would be handy.

[chris davison]

I can believe that I just tested mine in beaver lake.