Oh what to do...

sperho · May 31, 2007

huskydave said:
You can make a really handy portable pump out of those. Thats what I would do.

I have an old weedeater and a chainsaw, one of which I'd like to use to power a small pump to do some light irrigation work. Any ideas on a cheap, yet robust pump with a garden-hose to 1" or so outlet?

huskydave · May 31, 2007

They sell small pumps at your local hardware store that fit on the end of a drill that would be perfect for a weedeater you need to adapt the shaft on the pump to 1/4" square I believe to slide into the weedeater. I had a weedeater powered one and I used it a lot, bailing out boats mostly just set it up and let it run. I put a small bolt where the throttle pivots to keep the throttle in one spot and usually ran it at 3/4 throttle. I fabed up a little stand with a handle on the top in order to put it down anywhere I wanted.

pbtree · May 31, 2007

power toothbrush?

Lakeside53 · May 31, 2007

huskydave said:
They sell small pumps at your local hardware store that fit on the end of a drill that would be perfect for a weedeater you need to adapt the shaft on the pump to 1/4" square I believe to slide into the weedeater. I had a weedeater powered one and I used it a lot, bailing out boats mostly just set it up and let it run. I put a small bolt where the throttle pivots to keep the throttle in one spot and usually ran it at 3/4 throttle. I fabed up a little stand with a handle on the top in order to put it down anywhere I wanted.

It would work but I doubt the pump is designed for a 10,000 rpm motor. Maybe put the old gearhead up at the motor and drive from that? A typical weedeater puts out say 1hp.. so it can drive a pretty good sized pump if you get the speed geared down. Of course, starting torque sucks..

sperho · May 31, 2007

What are typical RPMs of chainsaw drive sprockets? Might be easier to adapt to a lower speed hardware pump that husky mentioned.

huskydave · May 31, 2007

rpms for drive sprocket on a chainsaw are about 7000-14500 at full throttle the weedeater runs about 5000 when it is pumping water at 3/4 throttle you can lower that if you put a bigger intake hose. I don't know what rpms they are rated for but for 20 dollars I gave it a try and in my experience it works well. I don't know of any readily available pumps that are rated for that high an rpm. a speed reducer with planetary gears inside would be best to put before the pump but who would go through all that trouble when they could buy a small rotary pump for 20 dollars and if it breaks your only out 20 bucks. I put about 300 hours on mine and the engine quit because my friend had it running with no load. The pump still works well it is cooled from the water flow and has two high speed bearings in it.

sperho · May 31, 2007

I found a drill pump at Northern Tool (online) that has a 3000 RPM max for $16. Sounds very promising.

vapnut257 · May 31, 2007

My neighbor down the street installs the old trimmer engines on bicycles. you peddle the bike to get it started, then the engine takes over. He works on all that 2 cycle stuff and has done several bike mods.