Petrol Powered Pressure Washer

[mrcheese]

Kind of thinking aloud so I hope it is OK to post here. I was cleaning out my shed yesterday I came across my old JCB petrol chainsaw. When the centrifugal clutch jammed I couldn't get spares so I bought another saw.
The old saw's engine still runs fine. It is 40cc.

The new saw is 50cc with 2000W output. So I guess the smaller engine is 1500W. My electric pressure washer 1300W. So my thinking would be to use the old engine to drive a suitable pump.

Do the commercial units cut power to the pump when water is not flowing?

Apart from a standard pressure washer pump are there other suitable pumps?
A pump that can tolerate less then clean water (such as a river or lake) would be good. I would add some sort of pre filter.

I go off road and being able to clean the worst of the muck off before leaving is good. Currently I use a hand pumped pressure bottle to clean lights, plates and windows. So a huge volume of water is not needed.

Good idea? Or just daft? I will keep an eye out for a dead pressure washer that I can take apart for more inspiration.

Paul.

 

[shenion]

At 40CC it is probably about 3HP. Most pressure washers use 5HP engines.

The chainsaw engine runs at about 6k RPM. The pressure washer engines run at about 3000RPM. I guess you could do a pulley setup to reduce the RPM.

Most dead pressure washers are due to the pump wearing out. The pumps normally are designed to run with a pressure feed, so you would have to have a tank and gravity feed rather than a suction line.

 

[world wide viking]

why not...

have you checked the torque on the motor and the needed on the pump? Good idea to use the old motor. I saw ( with no other resemblance) a old ford four cylinder ford motor where to cylinders where used as an air compressor......

 

[mrcheese]

I have no idea of the torque of the motor. I'd like to find a pump and just have a play. Just not sure where to source a pump. Ideally I want a self priming one.
Buying new would probably be too expensive. So I am looking for something I can pull a pump out of. I think this is the sort of project where I just have to keep an eye out for something to try.

 

[Pete.]

Pressure washers have positive-displacement pump usually. That's the type you need, low volume, high pressure, positive-displacement.

 

[world wide viking]

I'm wherry found of the recycle stations here in Norway, always some of the washers that are shoot or just dumped since they had last years color...
A good place for people like us that just wanna try to see if it works and try for free.
Any idea of the skid to put it in?
best of luck.

 

[the snooper]

At 40CC it is probably about 3HP. Most pressure washers use 5HP engines.

The chainsaw engine runs at about 6k RPM. The pressure washer engines run at about 3000RPM. I guess you could do a pulley setup to reduce the RPM.

Most dead pressure washers are due to the pump wearing out. The pumps normally are designed to run with a pressure feed, so you would have to have a tank and gravity feed rather than a suction line.

most diy washer here in the uk dont have a 3hp motor so that should be ok as long as the engine is geard as mentioned above as it will only produce full hp at a certain speed.

also some washers when not in use have a valve that recirculates the pressure back to the intake so this would be the type to go for .
the others switch the motor on when the pressure is released from the gun