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Karcher K4 Full Control change of gun!

40K views 136 replies 11 participants last post by  percymon 
#1 ·
Hi all,

I am looking at changing me Karcher spray gun. I have a K4 full control and I recently purchased a different lance with some better nozzles but unfortunately this did not work properly.

The gun was well under powered and was no where near as effective! I was looking a maybe changing the gun to Mosmatic one but don't want to spend a fortune if the jet wash isn't going to give the maximum pressure!

Has anyone else changed guns on a full control Karcher?

Thanks Rob
 
#2 ·
Having done a fair bit of reading and research into this topic I'll try to summarise what I've learned.

The "power" of the pressure washer has to do with the pressure that is developed at the nozzle. You may be aware that pressure comes about due to resistance to flow. The pump in the PW provides the flow, the nozzle provides the resistance.

Too little resistance (ie a nozzle orifice that's too big) = not enough pressure, and a PW that doesn't seem very powerful.

Too much resistance (ie nozzle orifice too small) and the pump will struggle, it may stop and start intermittently if the machine detects too high a back pressure. No use either!

What you need is the right size of nozzle - erring slightly on the side of caution (better to lose a little pressure rather than put unneeded strain on the pump). Have a look at this (PDF link) for a bit more detail and a handy lookup table. According to the Karcher product page (and specifically the specifications on page 14 of this PDF), your K4 is rated for 6.3 litres per minute at 11MPa, or 110 bar.

Using the table linked above, on the 110 bar column the flow rate of 6.3 litres per minute would suggest a nozzle between a 0.25 and 0.3. Note that none of this has anything to do with the gun you are using - it's all about the size of the nozzle. It depends on the lance you're using but you might be able to change the nozzle size (they are frequently available separately, sometimes with a quick release and sometimes with a thread).

If you can post a picture of the new lance & gun, I can try and suggest the best way to update the nozzle. It would also be well worth going back to the place you bought it from and asking them what nozzle size it is. My guess is that you've got a 0.35 or 0.4 that is reducing the pressure and hence effective power of your machine.
 
#3 ·
Having done a fair bit of reading and research into this topic I'll try to summarise what I've learned.

SteelGhost...

Thank you for replying!

You are right, but I did do some research into this before hand too. What I found was that a Karcher K4's should be at about nozzle 0.40, this is what I got so you are right. However. I did speak with the shop and he did say the K4 is normally around a 0.40 nozzle as well.

He could be wrong and it looks like he is, I got a quick release nozzle set up so I might just order a 0.30 or 0.35 and see if it helps. They are only a fiver!

What do you think?

Thanks Rob
 
#4 ·
Hi Rob - if you have a QR nozzle setup then you have a very quick way to test / resolve the situation. I would go to a 0.30 nozzle in the first instance - based on the flow / pressure table, I think a 0.35 would still be a bit big.

Worth noting you can get a set of all the angles for £12, might be better value than buying individually even if you only use the 15, 25 and 40 degree ones.
 
#11 ·
At the minute I have the standard Karcher K4 Full Control.

I use a stainless steal lance with a quick release end.

I think you might have the opposite to me. You might have a nozzle that is too small!

What size did you get? I know have 030!

Thanks
Rob
 
#17 ·
Assuming your K4 is the same specs as Rob's, you'll want 0.30 nozzle size (which is actually the correct nozzle size for a wide range of machines).

Problem is a lot of the cheaper hardware doesn't actually state the nozzle size so you have to hope or reverse engineer it from the specs they give and hope they're accurate!

Something like this https://www.ebay.co.uk/itm/Pressure...mm-Wash-Gun-/281229199895?hash=item417a910a17 with the right adapter to whatever hose end you've got, and a set of the nozzles I linked to in post #4 should do you right.
 
#18 ·
Assuming your K4 is the same specs as Rob's, you'll want 0.30 nozzle size (which is actually the correct nozzle size for a wide range of machines).

When you get a chance see what is wrote on the nozzle bit as stated before. If it is 030 then I am pretty sure it could be a dodgy gun!

I am debating whether to get this one. I do love a gadget and it might well be a waste of money but it looks good and makes it that bit easier and better to do the job.

https://obsessed-garage.myshopify.c...ic-spray-gun-wand-package?variant=33583399363

Thanks
 
#20 ·
He's basically found some high end manufacturers (ie Mosmatic, MTM Hydro) and cherry picked their catalogues to put together a well thought out package, but I don't really understand what he's done that's quite so ground breaking other than pick out nice versions of pretty standard hardware. It's all stainless and so on, which is fine, but unless you're washing down commercial kitchens or dairies or something, it's not actually needed. I take my hat off to the guy, he's identified his target audience (well off folks with nice cars who want a "proper" pressure washing package without having to think about it) but unless you really want to spend that money, I think you can get most of the benefits for quite a lot less money (and I will back up that assertion properly later!)
 
#21 · (Edited)
https://www.ebay.co.uk/itm/PRESSURE...AILINGWORLD-/182692303936?hash=item2a894f5440 - Suttner trigger gun with stainless swivel
http://www.ebay.co.uk/itm/New-3-8-P...Set-200-Bar-/330738035552?hash=item4d0185eb60 - QR for the hose & gun
https://www.ebay.co.uk/itm/New-M22-...Karcher-etc-/331937556926?hash=item4d490529be - allows female side of QR to join to an M22 hose termination
https://www.ebay.co.uk/itm/New-3-8-...Karcher-etc-/330690417763?hash=item4cfeaf5463 - 3/8 BSP male to male - joins male side of QR to the swivel
https://www.ebay.co.uk/itm/Pressure...-Male-B-S-P-/272665811100?hash=item3f7c26189c - gives the outlet of the gun QR capability (11.6mm QR plug)
http://www.ebay.co.uk/itm/Pressure-...elease-/281937374641?var=&hash=item8740d9afb7 - provides angled lance to connect to the gun, with tips that can either be used on the gun directly or on the end of the lance
http://www.ebay.co.uk/itm/White-PTF...509649&hash=item4d62844b1f:g:CkYAAOSw311Zt6bQ - a roll of PTFE tape to do the lot up with

By my maths that lot comes to a bit under £80 and is 95% as functional (the brass won't be quite as durable as the stainless) as the full on Mosmatic setup, if not quite as pretty :thumb:
 
#26 ·
Nice! He has obviously seen the demand for this quick release malarkey!!!

That looks pretty similar. Again you can see that extra bit of quality with the full Mosmatic setup but this one is impressive too. How much is it?

I also like the MTM Hydro Snow Lance haha.

I have spoken to Matt at Obsessed Garage and the postage is about £40 and will arrive within 4 days DHL!

Rob
 
#31 · (Edited)
Hmm, as I said either way I will be waiting until spring so will have a good think and by that time maybe both options will have been tried out on here and will have a bit more to go off. Has anyone in the U.K. actually bought a lance set up from Obsessed Garage.

Either way its a lot of money for a lance setup, I have wanted the OG one for a while and considering the price difference (I don't think is that much) I think I would get the OG one. It might seem daft or waste of money to some but I just wouldn't want to feel I was missing out for the sake a little more. Would definitely be interesting to see a comparison video between the two.
 
#33 ·
Hmm, as I said either way I will be waiting until spring so will have a good think and by that time maybe both options will have been tried out on here and will have a bit more to go off. Has anyone in the U.K. actually bought a lance set up from Obsessed Garage.
I'm sure I've seen a couple of posts saying that they were thinking of it. Can't remember anyone actually saying they'd pulled the trigger (ha!)

When I've got the last couple of bits sorted for my setup I'm thinking of doing some sort of video "walkthough" since this sort of thing seems to get quite a bit of interest. Might help you decide one way or t'other.

Thinking about whether it's worth it; the final cost for the Mosmatic is going to be around £155 for the gear, plus shipping, plus import duty / VAT. Given it's coming via courier you will definitely pay the duty, so I think you're talking well over £200 all in, maybe £230.

Good point SG...

The VAT & Duty will put another £40 odd on the full package! Including delivery that will be nearly £300.

However, I have another plan. My sister in law is off to New York in 2 weeks. I might be able to get it delivered to her hotel then she will bring it home! That will save postage and VAT & Duty!!!

What do you think? Surely that's the way to do it!
If you've got someone who happens to be able to get it there and bring it back then that does change the economics :thumb: Bear in mind it's going to be moderately heavy so your SiL might need to check how close she is to her weight allowance! Also, given it's a "gun" (albeit not that kind of gun) she might want to be ready for some nosey parker in the US to ask to see inside her case :lol:
 
#32 ·
Thinking about whether it's worth it; the final cost for the Mosmatic is going to be around £155 for the gear, plus shipping, plus import duty / VAT. Given it's coming via courier you will definitely pay the duty, so I think you're talking well over £200 all in, maybe £230.

Good point SG...

The VAT & Duty will put another £40 odd on the full package! Including delivery that will be nearly £300.

However, I have another plan. My sister in law is off to New York in 2 weeks. I might be able to get it delivered to her hotel then she will bring it home! That will save postage and VAT & Duty!!!

What do you think? Surely that's the way to do it!
 
#60 ·
Apologies for the change of subject, but as Mr. SteelGhost is so knowledgeable in such matters this seems as good a place as any to ask.

I have a billy-bargain-basement Nilfisk 105 with a plastic lance. I'm also hugely tempted by the Kraenzle group buy offer - not that I can justify the cost but still...

I have a decent SF lance with the requisite Nilfisk T-shaped quick release that I'd like to retain due to cost. (I assume these are threaded onto the lance but it almost appears bonded.)

I am building a new workshop and have the opportunity to permanently install the PW and make up a long hose reel, but had never considered a change of lance. What are the benefits of an ebay special going to be over my plastic jobbie?

...and should I buy the Kraenzle?!

Many thanks.
 
#61 · (Edited)
First of all, almost all snowfoam lances can be adapted to pretty much any machine. So no concerns there :thumb:

For me your post breaks down into three questions which I'll try to answer in turn.

What are the benefits of an ebay special going to be over my plastic jobbie?

The point about eBay is that there are all manner of companies selling pressure washer parts on there, and because they are frequently selling to pros doing Real Work (TM) (eg, cleaning wagons, heavy plant, farm machinery or premises, etc) they are selling gear that's much better quality and more durable than the made-to-a-cost stuff from Homebase or B&Q.

So it provides the possibility to specify your own trigger, lance, extensions, nozzles, etc etc. Plus because all this gear typically uses a standard set of connections, you're no longer restricted to whatever attachments your manufacturer sells. And, if your machine should fail and is not repairable, you can keep the nice gun, lance, nozzles etc and just change the machine (possibly with a new adapter). And because all the parts are interchangeable, you can replace parts that fail or frequently get spare parts and repair it yourself.

You can expect to pay a bit more for it though - for instance, the lance setup I suggested earlier in the thread is £65 - £80, depending on how you specify the connectors, which is the price of a whole budget PW.

So you get better quality, durability and repairability, choice of configuration, but at a greater financial cost (albeit one that you should only really need to spend once).

I am building a new workshop and have the opportunity to permanently install the PW and make up a long hose reel

A new hose, regardless of whether or not you get a reel, is a very worthwhile thing if you have a budget PW. Typically the stock hoses are made of thermoplastic which is liable to tangling and kinking. A "proper" rubber hose with steel wires is much more durable, as well as easier to handle. Replacing the hose with an aftermarket one provides the opportunity to get away from manufacturer specific terminations, since a good hose is an appreciable investment!

My PW came with a 10m hose but I found this wasn't as long as I really wanted, and it was taking a lot of time to get out and put away. As I pretty much always wash my car (or any other car!) on the drive in front of the garage, it made sense to get a longer hose with a reel and mount it on the wall. If you expect to use your PW mostly in the same place, then a reel makes a lot of sense (but if you're going for that option budget for a bit extra hose, you'll likely want it at some point!)

Permanent installation of a PW is also a nice idea, you can have all the power and water ready to go, with the tug of a hose and the flick of a switch you're all ready to go. The same comments apply as for the hose - if you're mostly / always going to use the machine in the one place, go for it. If you might want to take it to a mate's house, or around the back to do the patio, or whatever, then it's worth thinking about how to set it up so it's not too "permanent" :lol:

It's worth noting that some PWs have built in high quality hoses, guns and reels, and come with sturdy wheels (which is just as well since they are very heavy!) For instance, the K1152 TST. It has the "guts" of a HD10 but a very robust chassis with wheels, really good quality gun, lance, hose etc. If you look into what this would cost to do separately, well, you come to a number considerably greater than the cost of this machine, especially for the GB price. Plus it's all portable if you need it to be.

All of this brings me neatly to your last question should I buy the Kraenzle?!

If you can afford one, absolutely. They are superb quality, and while they are not always the absolute best performance for the price, the reason to buy one is the knowledge that in the unlikely event of a fault, you'll be able to get spares, exploded diagrams, etc for years to come.

Again if you can afford it, the K1152 TST is very good value given how much it would cost to get all those things separately. However if you want to do things piecemeal and spread the cost, you could start off with a new hose (probably the best bang for buck upgrade on any budget machine) and then upgrade the gun, add a hose reel, etc, at a later date.

One final point - if you have any ideas of running a Kraenzle off stored water eg collected rainwater, you want to go for a machine with a 1400rpm motor. If you'll be running it off mains water (or you're prepared to install a pump to use rain water) then motor speed doesn't matter per se.

Edit: Just seen that Elite are offering the K1050 TST for £420 which is a stonking bargain as long as you don't need a 1400rpm machine (see above).
 
#62 ·
What a great and detailed reply, thanks very much. Took some digesting! One thing I had wondered - do the higher spec machines (especially the bypass- rather than dead-end-style) allow you to vary the flow rate with the trigger?

I would prefer to go piecemeal - that way I can use the Nilfisk pump until it dies. But of course this increases the cost, especially as the group buy is here now. I will be using rainwater eventually so have been looking towards the HD7. I may ask if they can supply the motor/pump unit alone so that I can spec my own eBay special lance, etc. so I don’t end up buying duplicates!

I think in truth I’m hoping that the little Nilfisk will continue to soldier on for another year or two - if only because I’m not a great fan of replacing things for the sake of it. But like you say (and after looking) if the cost of a decent reel and lance is close to that of a whole machine - am I almost best to take the opportunity to sell the old one while it still works.

But ultimately no one can answer these questions but me! (And the credit card company!) Thanks again.
 
#63 ·
What a great and detailed reply, thanks very much. Took some digesting! One thing I had wondered - do the higher spec machines (especially the bypass- rather than dead-end-style) allow you to vary the flow rate with the trigger?.
I've yet to see or even hear about any machine where the trigger wasn't a binary on / off switch. The Kärcher "full control" models have variable flow on the lance but you're reducing the cleaning power that way. Overall I'd say you generally want to use the full power of your machine, but vary your nozzle, technique or both to suit the job at hand.
 
#67 ·
Ha, "call for price" - probably means I can't afford it! 16A no worries, got a 50A incomer to the garage and a couple of 20A radials set up as I had an idea that big power consumers might appear at some point!

From looking around at baby industrial type machines all ready made up, the Kraenzle is hard to beat for the price. Having said that, if these guys can turn a profit on this then it's just a case of finding the right pump at the right price and the eBay special is a goer.

Reckon I can bring a pump and motor in under £200... maybe, just. Lance at £80 and hose reel £120. Pretty mean setup with all the quick releases etc all in.

https://bepressure.co.uk/honda-pres...re-p1515epn-portable-electric-pressure-washer
 
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