Kraft Stahl petrol washer

Good morning all.

I recently bought a Kraft Stahl 3800 psi cold water washer with a 5.5. Hp 4 stroke engine and - with a set of exchangeable nozzles it went well for a few weeks. I did look for a source of advice/spares/etc. but it is Chinese and I hoped it would have a long life, - like so many items I have. I do h ave a very basic sheet, but it was second hand and pretty cheap.

To start it I have to tie a bit of string round the trigger, as it is not p ossible to pull the cord against a closed tap. I an not happy with this ar rangement as the gun, - unless wedged somewhere tends to fly around squirti ng everything!

I was using it to clean out the troughing on a roof and came down the ladde r after wedging it, but the string came undone and for some time it was run ning against the now-closed trigger. When I tried to continue I found that the pressure was now very low and un-useable. I thought maybe the inlet f ilter had got blocked as the motor was running fine and did not seem to be labouring, but it was all clean. The compressor is quite small and I am te mpted to dismantle it all to see what has gone wrong. There is no chance of any warrantee either.

Has anyone had a similar problem, or got the exploded diagram or some form of manual, before I start undoing all the allen screws to get it apart. The re is no sign of any input filter.

Any comments welcome as, apart from a few complaints, it has been a very us eful addition to my equipment.

Thanks and regards George.

Reply to
George
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It isn't 3,800 psi with a 5.5hp engine - unless they have found a way to change the laws of psychics :-)

There should be an unloader/bypass valve to enable you to do that. May be missing on a cheapo.

Depending on how long it was running with the trigger closed, it could have seriously over heated & damaged the pump seals. Any makers name on the pump? Or a photo?

Doubt its the inlet, more likely the pump seals.

Just looked online. The thing with the spring, above the inlet is the bypass valve. Does that move in/out when the trigger is opened/closed?

Reply to
The Medway Handyman

Laws of psychics eh? If you concentrate hard enough it will work :)

But more seriously no reason why there needs to be a relationship between power and pressure. If you think of the old simile that pressure=voltage and flow=current - it's actually correct here.

1 volt at 1 coulomb per second (1 amp) equals 1 watt. 1 pascal at 1 cubic metre per second also equals one watt.

Of course 3800PSI is about 26 MILLION pascals, and 5.5HP is about 4Kw, so you end up with a flow of about 1/6 of a litre per second if I have the arithmetic right.

Andy

Reply to
Vir Campestris

In the trade, they use a simple calculation to compare the cleaning effect of different machines;

Cleaning Effect = Pressure (bar) x Flow (litres/min) / 600

Reply to
The Medway Handyman

4 stroke engine and - with a set of exchangeable nozzles it went well for a few weeks. I did look for a source of advice/spares/etc. but it is Chine se and I hoped it would have a long life, - like so many items I have. I do have a very basic sheet, but it was second hand and pretty cheap.

possible to pull the cord against a closed tap. I an not happy with this arrangement as the gun, - unless wedged somewhere tends to fly around squir ting everything!

der after wedging it, but the string came undone and for some time it was r unning against the now-closed trigger. When I tried to continue I found th at the pressure was now very low and un-useable. I thought maybe the inlet filter had got blocked as the motor was running fine and did not seem to b e labouring, but it was all clean. The compressor is quite small and I am tempted to dismantle it all to see what has gone wrong. There is no chance of any warrantee either.

m of manual, before I start undoing all the allen screws to get it apart. T here is no sign of any input filter.

useful addition to my equipment.

Thanks Dave, I have taken some photos of it, but it will take a day or so to post them on my website, can I put them here? If so I don't know how. You do mention that you looked it up on the web. That is what I was trying to do! I could not find it however. If you can show me where it is, I wo uld be most grateful. It was not pushing against the closed tap for more t han a minute or two and it was not labouring or overheating as far as I cou ld see.

Regards George.

Reply to
George

They sell them on flea bay, only saw a picture.

Reply to
The Medway Handyman

. Hp 4 stroke engine and - with a set of exchangeable nozzles it went well for a few weeks. I did look for a source of advice/spares/etc. but it is C hinese and I hoped it would have a long life, - like so many items I have. I do have a very basic sheet, but it was second hand and pretty cheap.

not possible to pull the cord against a closed tap. I an not happy with th is arrangement as the gun, - unless wedged somewhere tends to fly around sq uirting everything!

ladder after wedging it, but the string came undone and for some time it wa s running against the now-closed trigger. When I tried to continue I found that the pressure was now very low and un-useable. I thought maybe the in let filter had got blocked as the motor was running fine and did not seem t o be labouring, but it was all clean. The compressor is quite small and I am tempted to dismantle it all to see what has gone wrong. There is no chan ce of any warrantee either.

form of manual, before I start undoing all the allen screws to get it apart . There is no sign of any input filter.

ry useful addition to my equipment.

r so to post them on my website, can I put them here? If so I don't know ho w. You do mention that you looked it up on the web. That is what I was tr ying to do! I could not find it however. If you can show me where it is, I would be most grateful. It was not pushing against the closed tap for mo re than a minute or two and it was not labouring or overheating as far as I could see.

Well I took the top off the end of the pump leaving the swash plate piston s behind and in the valve cover I found that one of the incredibly delicate plastic assemblies, - sprung loaded, had broken up, - the one nearest the inlet pipe. It will be impossible to repair this without the correct kit a s they are tiny and look quite unsuitable for the job. It may have been th e vibration of bubbles going through the pump that caused this disintegrati on. Unless I can contact Kraft Stahl, I think it is a write off. What a sh ame. No identity or anything on the pump, at all.

Regards George.

Reply to
George

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