Can you get 40psi out of a garden hand spray?
 

I want to recondition the injectors on my 740, and I'm trying to put together a kit to do this offgrid. I've bought a pulse tester, but I need to generate 40-50 psi to push the cleaner through the nozzles. I've seen a wide variety of creations for this in various youtube videos, but I haven't seen anybody try to use a garden hand spray. It seems to be the ideal solution if you can build up enough pressure.

My 5lt Hozelock sprayer blows the relief valve at around 30psi. I think you will struggle with 40-50psi as that pressure isn't needed or desirable for the sprayer to do that which it was designed for.

My sprayer has '2.5 bar max pressure' printed on it, which is 36 psi, so I'd suspect that's what the pressure relief valve is set to.

You might be able to override the relief valve and get a bit more out of it, but I have no idea how much of a safety margin has been built in.

Do you have a compressor?

The obvious question is, why don't you try one of those then ?

It's a bit like saying there are lots of ways on line on how to trim a moustache, but I've got this perfectly usable pair of shears in the shed ?:wink_smile:

I once (when I was much younger and much more foolish) made a device for pressure gunking engines by getting an old garden sprayer, drilling a hole in the side (can't remember what size) and screwing in a male PCL quick coupler so I could connect it to my compressor. I ran it at 80 psi and it worked fine, when I first pressurised it I did so with a long airline at a distance.

Usually there is a x2 factor of safety so a 30 psi sprayer should withstand 45 PSI.

To be clear - I'm not recommending this - just pointing out that I once did it and got away with it.... a compressed air vessel with say 7 litres volume can make a right old mess even at just 40 psi.


(This: https://www.ebay.co.uk/itm/324109800...kAAOSw~yFiUEu-)

hello there , why not simply use a fuel injection pump with a pressure regulator ?

Definitely enough pressure & pretty much designed for the job and if you capture used fluid , make sure you have a filter to remove any gunk washed off .

Offgrid injector testing
 

I have got a compressor, but it is a bit old, and powered by a Petter stationary engine. It seems to be a bit of an overkill to use that.
The object of the exercise is to do as much maintenance offgrid as possible. So injector testing and cleaning needs to be done in the woods, or on the beach. I bought a pulse tester, as this seems to be an inexpensive option, and I've got an AGM battery that I can use as a power source. I just needed something to push the cleaner through the injector as it pulses. I'm considering using diluted card cleaner as the agent. Is there any disadvantage in using this. I thought it might be better than my universal choice, which is diluted vinegar.

Right so this is what id do then.
Fit the sprayer with a car tyre valve. Just drill a 10 mm hole and pull it through just like the tyre fitters do.
Start filling the sprayers vessel slowly with compressed air via a tyre inflator(the type yout Ats,Kwik fit type places use.
You can monitor the pressure in the vessel and see at what Psi the blow off valve triggers if there is one fitted.

It also depends on how old/ how good the sprayer is.

I recently had an incident with my old plastic one where as I pumped it up before the safety pressure valve had even started to move a small piece of the sidewall blew out!

Time for a new one.