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Read this if you own a Karcher..
10 May 2020 15:29 #222105
by DAGZOOK
Read this if you own a Karcher.. was created by DAGZOOK
This isn't Jimny related as such, but I thought this would be useful information for everyone out there who owns a Karcher. As everyone reading this owns a 4x4 I suspect that's most of you..
My Karcher K4 premium had developed a really strange intermittent electrical fault, where it would trip the RCD in the garage fuse board. The machine would trip the fuse sporadicly with no prior warning or loss in performance. After a second electrical trip in 48 hrs, I knew the machine was going to be coming apart. The pressure washer was just outside of warranty period (I know Sod's law).
(RCD's "residual current devices" do not protect against electrical overcurrent i.e drawing too much power, they protect against short circuits, imbalances between L + N, faults to earth etc. So in essence if your appliance is tripping one, you can be sure it has an electrical fault within.
So I pulled it apart and this is what I found...... :blink:
Karcher K4 premium water cooled motor.
First test I ran was electrical continuity (Ohms) through the main lead, motor and through the switch/capacitor housing (white thing) using a multi meter. All was fine.. very low in fact the head scratching continued.
So that's it then, motor is coming apart! Cylinder head, Capacitor & switch housing removed Continuity tested again on the bench (all good). Notice the little electrical Piezo? the white electrical housing sits on top of that, along with the actual high pressure pump. That is the means of sending power to the electrical motor below. A series of tap washers and that little rubber gasket is all that's stoping the machine from arcing out! No sign of water + arcing here though - so the search continues.
So the main lower motor housing was then split apart:
Oh dear... As you can see from the above photographs, the water cooled void of the motor (see where my screwdriver is) seems to have been 'letting by'. The cheap o-rings aren't up to the job, they didn't seem like a nice snug fit. As you can see there seems to be arcing marks present on the main internal motor housing, right beside the 2kw coil.. :woohoo: we've found our tripping source!
So the reverse begins, I built the motor housing back up using RTV gasket sealant.
The cylinder head was then stripped inspected and re-greased with moly axle grease - as the existing factory grease seems to have been contaminated with water and gone all mushy. The machine works by a motor spinning an offset wobble plate, this compresses the three little valves in sequence which in turn provide compression to the water pump above, Quite simple, just assembled cheaply.
See continuation...
My Karcher K4 premium had developed a really strange intermittent electrical fault, where it would trip the RCD in the garage fuse board. The machine would trip the fuse sporadicly with no prior warning or loss in performance. After a second electrical trip in 48 hrs, I knew the machine was going to be coming apart. The pressure washer was just outside of warranty period (I know Sod's law).
(RCD's "residual current devices" do not protect against electrical overcurrent i.e drawing too much power, they protect against short circuits, imbalances between L + N, faults to earth etc. So in essence if your appliance is tripping one, you can be sure it has an electrical fault within.
So I pulled it apart and this is what I found...... :blink:
Karcher K4 premium water cooled motor.
First test I ran was electrical continuity (Ohms) through the main lead, motor and through the switch/capacitor housing (white thing) using a multi meter. All was fine.. very low in fact the head scratching continued.
So that's it then, motor is coming apart! Cylinder head, Capacitor & switch housing removed Continuity tested again on the bench (all good). Notice the little electrical Piezo? the white electrical housing sits on top of that, along with the actual high pressure pump. That is the means of sending power to the electrical motor below. A series of tap washers and that little rubber gasket is all that's stoping the machine from arcing out! No sign of water + arcing here though - so the search continues.
So the main lower motor housing was then split apart:
Oh dear... As you can see from the above photographs, the water cooled void of the motor (see where my screwdriver is) seems to have been 'letting by'. The cheap o-rings aren't up to the job, they didn't seem like a nice snug fit. As you can see there seems to be arcing marks present on the main internal motor housing, right beside the 2kw coil.. :woohoo: we've found our tripping source!
So the reverse begins, I built the motor housing back up using RTV gasket sealant.
The cylinder head was then stripped inspected and re-greased with moly axle grease - as the existing factory grease seems to have been contaminated with water and gone all mushy. The machine works by a motor spinning an offset wobble plate, this compresses the three little valves in sequence which in turn provide compression to the water pump above, Quite simple, just assembled cheaply.
See continuation...
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10 May 2020 15:38 - 10 May 2020 15:59 #222106
by DAGZOOK
I also used RTV sealant on the Cylinder head O-ring.
The machine was then bled, and bench run with great success.
I ran the machine continually for about 20 minutes with a high pressure lance whilst drinking a cup of well earned tea. No more Tripping, the machine sounded quieter and also featured slightly increased pressure at the lance.
In summary, I think Karcher machines are over priced and cheaply made. There seems to be a couple of minor design flaws present here with this K4 premium, not what you expect for £300+. If you suffer a similar issue with your water cooled Karcher the above checks for water around the cylinder head and within the motor housing should be your go to! Check for chalky aluminium corrosion and arching marks (as photographed above)
If I was to have my time again, I'd buy a small portable petrol pressure washer. Water and electricity will never be friends
Hope this helps a few others!
Replied by DAGZOOK on topic Read this if you own a Karcher..
I also used RTV sealant on the Cylinder head O-ring.
The machine was then bled, and bench run with great success.
I ran the machine continually for about 20 minutes with a high pressure lance whilst drinking a cup of well earned tea. No more Tripping, the machine sounded quieter and also featured slightly increased pressure at the lance.
In summary, I think Karcher machines are over priced and cheaply made. There seems to be a couple of minor design flaws present here with this K4 premium, not what you expect for £300+. If you suffer a similar issue with your water cooled Karcher the above checks for water around the cylinder head and within the motor housing should be your go to! Check for chalky aluminium corrosion and arching marks (as photographed above)
If I was to have my time again, I'd buy a small portable petrol pressure washer. Water and electricity will never be friends
Hope this helps a few others!
Last edit: 10 May 2020 15:59 by DAGZOOK.
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