that's probably the unloader valve all it might need is a quick dissasle to see whats gumming up the works , as all I was able to find for sale for that model here was a new gun and the soap injector for about sixty bucks each , you might have to look around in the Uk for one as that's were there most popular
If the unit has seen a few tens of hours of work, it may be the brushes. My unit was going fine, then for a minute or 2, it was like someone was winding the inlet power down then back up. Then it stopped and would not start. I replaced the brushes and it now runs as it did. Several 10's of hours old, but not ready for the scrap pile yet.
I had the same issue and after much exploring I discovered just a tiny bit of corrosion in the switch. To repair, remove the squegee section, and water bottle, so you just have the base unit. Then remove the bottom plastic cover and unfasten all the screws. Now remove the switch. With a fine Exacto knife and a magnifyer remove the switch and open it. Check it for corrosion this is whats causing it to stay on. Carefully scrape out the corrosion with the Exacto tool and then carefully reassemble. The light should switch off. You can also test it before reassembly just to make sure all the corrosion is gone.
There are no schematics available because the manufacturer doesn't sell parts for the gun. The spring usually goes right into the end of the hose, then the little bullet like valve follows. Did you know you can buy a new gun for about $22.00 Canadian?
1 water inlet filter clean ?? not limed or ??
2 nozzle clean.
3 pressure control valve properly screwed
Sometimes water hoses are provided with a slot at the hose connection with an internal water seal, which is the wrong way to the water tap instead of to the machine
Did you check if the igniters? they may be cloged up with ****. Unscrew the Sight glass on top of the boiler and run the machine (in cold or hot mode, doesn't matter, as the igniters are running all the time) and see if there are working, you should take them out anyway and give them a wipe with a rag as general maintenance item, and when you put them back in there should be about 5mm gap between them.
Less common reasons for the boiler to not work - Faulty fuel solenoidvalve, (You should hear a click sound about 5 - 10 seconds after you pull the trigger) - Dirty fuel filter, Take a look at those simple things and let me know if its any of these. I have a Karcher HDS 750 1989 Year model This machine just keeps going, it's had a fairly tough life but it has stood up to it all, i hadent spent anything on it until about 6 months ago when i purchased a new fuel pump for it as the old was wasn't pushing 170PSI to the Disiel injector it had slowly droped 70psi, and it doesn't create a hotter burn in the boiler, but still very good for a 19yr old pump, other than that thats all it's needed, it's still going strong to date Very robust machine. my e-mail is [email protected] Cheers Matt.
Run a hose from the inlet (Using appropriate connector) to a tank of water, pond, lake river Etc.
You will need a filter box on the submerged end of hose . You can easily make one out of a plastic container with the side cut away and replaced with very fine mesh.
Is the motor running? If not, did you check the starting capacitor?
Did you check motor windings for continuity? Did the pump seize? Is electricity reaching the unit - wire ok?
I see this lots of times , the detergent tank will only mt in the low pressure mode of nozzle , this is the only way a siphion will develop inside the soap tank and then high pressure can be used later to wrinse the item off well using just water
Hi Stephen:
Don't know where you are, but in my location here in Canada, the local LORDCO parts store has a large selection of pressure washer accessories.
I'd suggest that you try to find a similar equipment supply retailer.
Cheers
I think there is hanging a by-pass (auto-stop) on lime after using it a long time can happen if after a long time before the first use the autostop or by-pass is a point where is placed mostly a microswitch that will standing in a open circuit state (activated and the spring is not strong enough to push the bypass back or i don know for shure if the material is ordinary steel or a phosphor bronze spring. but there is in much brands of pressure washers a lot of problems with that kind of technics if you use it not every 2 months 1 time then its giving problems the old models have a bypass only that the motor can run in non-load mode have the most pressure washers no problems, but there will be the problem with autostop / microswitch.
https://www.youtube.com/watch?v=bm5XoFrAHyE
A bypass is by most pressure washers a plastic frame where is a microswitch inside look at this maybe you have luck if the spring is in good condition and only lime because the bypass have a broken spring most times the parts are expensive and in a complete cuff kit only , i am not a Karcher specialist only Kraenzle and Efco so i do not know how the service parts will going in your Country. succes
