Mounting a pump quandry

ncclaymaker

Sr. Member
Aug 26, 2011
370
315
Champlain, NY on the Canadian border.
Detector(s) used
Minelab 1000, A Motorized Power Glider Trike, 17 foot travel trailer behind my Jeep. 4" suction dredge/high banker.
Primary Interest:
Prospecting
Here's the deal. Already have a great pump and propulsion system, but... some of us in life really need a plan "B". Since looking at the prices of "branded" equipment, ouch. What would the difference be, if I mounted a pump UNDER a 12 hp riding lawn mower engine. In other words, the vertical pulley shaft attached to a pump drive shaft.

I can buy used riding mowers for about a $100 or so. Why would anyone spend big bucks for a horizontal shafted motor, when vertical shafted ones are more common. I had a riding mower for 14 years before it rusted out, the motor was still running strong. Durability isn't a question.

The most important question is - does anyone know if this mounting style would cause an early pump failure? I'd like to get some thoughts on this mounting style before I try it as a plan "B".
 

Gramps43

Full Member
Feb 27, 2011
207
27
Tillamook, OR
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White's 4900/D Pro Plus
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Prospecting
As long as your foot valve dangles in deep enough water the pump shouldn't starve. If you do it Russ's way you'll have the build a water tight tube from the pump to the engine to keep the pump bearings dry.

Gramps
 

nuggy

Sr. Member
Aug 22, 2010
460
62
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Fisher Gold Bug Pro, had; Minelab Eureka, Bounty Hunter, Garrett, Fisher and Whites.
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All Treasure Hunting
My first dredge had the pump under a vertical shaft engine. It worked well, when I could get the dang thing started.

If the pump is actually underwater, no pump energy is used to lift it - so will have more water pressure coming out than the same engine pump combo that's having to lift it's water.

Hardest part is getting the crankshaft machined to fit the impeller and spaced just the right distance to center in the pump casing. Of course you can belt or chain drive the pump, but I don't recommend running these underwater.

Good luck with the project, Nuggy.
 

russau

Gold Member
May 29, 2005
7,285
6,745
St. Louis, missouri
Gramps43 said:
As long as your foot valve dangles in deep enough water the pump shouldn't starve. If you do it Russ's way you'll have the build a water tight tube from the pump to the engine to keep the pump bearings dry.

Gramps
Gramps he talking about his pump mounted under the eng. like keene used todo. then their wouldnt be a need for a foot valve.
 

Gramps43

Full Member
Feb 27, 2011
207
27
Tillamook, OR
Detector(s) used
White's 4900/D Pro Plus
Primary Interest:
Prospecting
Russ,

My imagination shows the engine mounted to the frame that holds the pontoons in place. If the pump is mounted directly to the bottom of the engine my imagination says it wouldn't be in the water and you would need a short piece of hose and at least a screen attached to the pump. If you were building, or wanted to mod an existing, dredge then you could build the frame with the vertical shaft engine mind and lower it's mounting position.

Gramps
 

russau

Gold Member
May 29, 2005
7,285
6,745
St. Louis, missouri
in light of this, the original poster needs to say if hes using a production frame or a homemade frame so that a educated guess would be in order. but your correct in that if he does use a production frame, he would need to use a hose/footvalve to get water and it would be a real pain priming the pump in that type of setup..wereas if hed do the pump in the water ,as Keene did, it would be primed all the time.but he needs to say how he wants todo it!
 

sniffer

Gold Member
Dec 31, 2006
5,906
58
Kansas
Detector(s) used
XP DEUS
I would forget the used mower engine and go to harbor freight and buy a clone motor for your application. I've got 2 of them and I've been using them pretty hard for around 3 years. the only problem I had was the fuel line is made from cheap pvc line and it split. I replaced it with a rubber line and back to working great. easy to start and maintain, decent size gas tank and cheap. if one ever goes bad, I'll go back and buy another
 

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