Hmmm ok , Its hard to tell without looking at it personally but just to remove another other doubts... Have you changed the hose lately going to the pressure washer ? Is the water that is going to your machine hotter than usual. - I don;t know where you live but for me the first few minutes after turning on the water its really hot because its been solar heated and its pretty close to boiling hot. Is there any damage to the your garden hose which would cause it to suck in air along with water ? But it seems you have already looked at these problems so at this stage the damage seems to be done so I am listing potential reasons for the problem and not cures, sorry about that. Usually though ,when the whole pump has broke it will show a lot more symptoms. If you are having trouble removing that plastic nut try to use a socket set and not a spanner.The spanner will for use cause the side to get wore down. The "start/stop valve" could be the unloader valve which has a spring inside it to control the pressure.... maybe a surge of air has forced it into its current position where its now difficult to remove. However I should warn you that if it is the unloader valve that when resetting,it needs to be in the correct setting otherwise its never going to be at the right pressure. If it was me and I was trying to fix a big gas powered pressure washer I would stay away from it but since its a somewhat cheap electric one and to buy a new pump would almost cost the same as a new pressure washer I wouldn't mind having a play around with it in the hope it works fine again. Sorry I couldn't be of more help. The electric washers are so picky and if the slightest part isn't doing what its supposed to be doing well then the whole things breaks. Here is a link that might be useful: I found this earlier... maybe it will help a little This post was edited by Gav104 on Thu, Jun 6, 13 at 23:09

Hi all, am new here after Googling problems on Karcher 2400 HH purchased at Costco about 5 years ago. Having the same pressure problems as many. I have broken the attachment fitting off the end of my trigger gun and am awaiting the arrival of a new one that I ordered from PressureParts.com. They informed me of this unloader problem. So I get to it and can't get it out either. Couldn't get any tool in with that cross member in the way. Naturally I hadn't got here yet before loosening the pump front and spilling oil. Doh!So pulled the whole thing off from engine and struggled but got the spill valve out with needle nose vice grips. Not really caked up at all but O rings were brittle and beat up looking. So I'll get some new o rings and get it it greased up while waiting for the new trigger gun. As well as getting some of this unobtainium oil and either topping up or replacing. Like others have mentioned it doesn't look as good as one would hope it might. Apparently a lot of these guns broke like mine (where the tube is soldered to the threaded fitting) and they have redesigned the plastic housing to better support that joint. Hope to have some good news in a week or so and share any thoughts and experience as many of you have done. Thanks to all!

After reading all of the posts here, i wonder how in the world our relatives cleaned things up without a pressure washer!! Why, they used a broom or mop, with liberal use of soap and muscle! Never had to worry about the things breaking--oh, maybe a mop handle, or the broom lost some bristles, but they never had to borrow the neighbors fancy power washer, which weren't available 40 years ago, except for commercial use. Seems to me, there's a sucker born every minute, reinforced by the stories of all the troubles apparently inherent with powered pressure washers! And--if the thing ain't made by an American company, don't buy it! and especially not if it has Chinese made parts! Back when i was a kid (the 30's) toys were imported from Japan, that were of such inferior quality, the stores sold them really cheap! And, the only thing that came from Japan that we took notice of was Pearl Harbor! Rusty

Only other advise or I have other than what posted is. Now don't tell anyone about this----Buy a can of CARB. CLEANER, read the instructions and warnings, and clean the carb as suggested. Don't leave gas in it when you put it in long term storage. IMO anthing over two or three months is long term storage ifyou do the gas just gummed up the carb. small passages IMO starting fluid is a waste of money, use carb cleaner as a primer you get better cleaning action and it do evaporate as quick, but quicker than gasoline. If you do decide to buy it Don't get sucked in on the Small engine carb. cleaner in the very small can, you just pay more for less. I buy the big can for cars choke and carb cleaner, injector cleaner, or throttle body cleaner don't matter unless you have throttle body or fuel injection then only use that formula.