Keene p350s pump question

[Mgumby16]

So last year i picked up a semi homebuilt 5 inch dredge for a steal. The frame and floats are garbage but the rest is all pretty much brand new keene parts.

I have been debating on selling the motor and pump because it is a briggs 18hp opposed twin and a keene p350s pedastal pump, which in my eyes is overkill for a 5 inch dredge at the depths i normally dredge at.

My question is if i ditch the huge 18 hp motor and hook the pedestal p350s to say a 6.5 hp engine that is modded and now producing about 10 hp, or a 8 hp engine will this work to power a 5 inch dredge, or even a 4 inch?

It may be that i just have to try it and see since its a rather odd engine/pump combo to dredge size match up.

Thanks for the input!

 

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[N-Lionberger]

I ran a p350 on an 8hp BS a season on my 4" I had the tweak the box to handle the increased flow.

 

[okbasspro]

A Proline 400 will do the trick on a 6.5 Honda

 

[Mgumby16]

okbasspro -

I know a proline 400 and honda 6.5 will run a 4, but i dont have one, Im just trying to work with what i have. If i but this setup on a 4 inch it will be a 16 inch wide overunder box. If i put it on a 5 inch it will be normal 20 inch wide box.

N-Lionberger - Do you know which impeller your p350 had? I think mine has the one that keene says requires a 16hp or larger motor. I would think with a 10hp motor attached it would power a 5 inch, or a 4 inch overunder box ok.

Thanks for the input.

 

[winners58]

its a matter of engine torque compared to the impeller bite.
a diesel motor would be ideal, they can be expensive.
I would say the 350s impeller might work ok on an 8hp
just wouldn't have the umph to run a 6 inch
a 5" or 4" would not be optimal but seems like you could get it to work,
I took a pump off a 5hp and put it on a 3.5Hp
it would start up at the 3600rpm then when the back pressure hit the jet
it would be like shifting gears and could tell it was using all its torque just to keep up.
work fine, seamed like it used more gas than it should.
not sure if older 8hp or mid size impeller($195) fits in a 350s housing you'd have to ask if they are different.
Keene pump parts
could give Pat Keene a call he might have some options or tips to make it work.

I have an 11hp on my 5" with the older impeller.

 

[N-Lionberger]

Not sure about the impeller, it's the stock setup for an older Keene 5" if I'm not mistaken. It had more than enough power to run my 4" I have dialed back to a 2x2.5" DK nugget pump on a 6.5 hp.

 

[winners58]

if you could find hose, jet & flare you could run a mini 6" using your 20" box.
mo money, mo money...

 

[Hoser John]

That is a great pump but my only experience was with a 18hp on my 6" triple. VERY good pump but why do you think it's a 350s in particuliar?John

 

[jsurddy]

That is a great pump but my only experience was with a 18hp on my 6" triple. VERY good pump but why do you think it's a 350s in particuliar?John View attachment 1697524

I’ve seen this pic of you dredge before and thought it was a 5”. Did you modify an old 5” or did that box come in a 6” also?

 

[Mgumby16]

John - I think it is a p350s, cause someone before me wrote p350s on the pump with sharpie. So i may not be. I happen to have a 6.5 predator motor that has been modded to produce about 12 hp, so im going to get a lovejoy connection and mate the two up and see if it will power my 5 inch. Ill be sure to take video of it. Should be interesting.

If it doesnt work, ill sell the pedastal pump and buy a dahlke dp500 on a subaru 7 hp motor.

 

[jsurddy]

I think the issue you would have with using a smaller engine is that it would have a hard time staying in it’s optimal operating rpm range. If you are running at lower rpms then you arent hitting the peak power of the engine. They change the angle of the impeller blades to allow the different size engines to run optimally. Something that would likely work pretty well for you at a small cost is putting a belt drive on the pump and giving it an under drive, or gear ratio reduction. That would allow the engine to run at it’s best rpm range and the pump would put out about as much flow and pressure as it would with the proper impeller and a direct drive.

 

[Hoser John]

It was born a 6" and yes box /floats/pump etc modified. I had a 5" triple also many years ago. I've owned/operated many dozens of dredges over the past 40+ years, 2"-10". John

 

[jsurddy]

That pretty neat. I kind of figured that box could handle the flow of a 6”.

 

[G1sammons]

I have the same pump but on a 24 hp Honda and it’s a bad ass . On a old triple modded out .

 

[G1sammons]

But I’d think of maybe a 10 at least just throttle down to find the flow your looking for !

 

[G1sammons]

I’ve seen this pic of you dredge before and thought it was a 5”. Did you modify an old 5” or did that box come in a 6” also?

Love that dredge john have the same unit !on 8 floats just wish I had a place to run it !

 

[russau]

That is a great pump but my only experience was with a 18hp on my 6" triple. VERY good pump but why do you think it's a 350s in particuliar?John View attachment 1697524

John , Those were the day's my friend , I thought they would NEVER END ! Hopefully they WILL return! GOOD LUCK and STAY SAFE !!!

 

[BigCrunch]

Hello Hoser John, Your 6" triple how did you trailer that thing around? 8 feet wide or close and 1000lbs to it I recall. If you have pics I would be interested in seeing them. take care.

That is a great pump but my only experience was with a 18hp on my 6" triple. VERY good pump but why do you think it's a 350s in particuliar?John View attachment 1697524

 

[N-Lionberger]

What is the difference between the 350 and 350S?

 

[winners58]

Keene Eng.
p350 is for 8 to 13 hp they also have 3 different bite impellers, one for 8hp, one for mid size(9hp) and one for 11hp+
P350S is for 18hp+ & P355S pedestal
PHP500 is for Honda GX390 (13hp)
P1500 is for 35HP+ (free standing needs coupling)

there is a difference between the P350 and P350S housing because they sell the two separately. (part #301 & #301S)
only way to tell is to have measurements when you ask Pat Keene