Weed sprayer woes

[MisterBoy]

I've got a manual pump sprayer bought ~4 years ago. It's very similar to this model (https://www.amazon.co.uk/Spear-Jackson-Action-Pressure-Sprayer/dp/B01CI55GWG)

I've never got on well with it. From day 1, every time I start it sprays wonderfully but this is erratic even though I keep it pumped up. One minute it's a beautiful wide mist, the next it's a single piddling jet.
I'm constantly fiddling with the nozzle, tightening/loosening every 2 min which sort of works but makes the job far slower and means my hands are constantly covered in whatever chemical I'm using.

I've cleaned the nozzle and it makes little difference. Is it just because it's cheap?

The job I currently want to do is treating about 600m2 of lawn with moss-treatment so I want a wide, even spray and I don't trust my sprayer. Googling about a bit there's clearly a lot more to it than I thought, different nozzle types and so on.

Should I toss this and buy something better?

 

[lostinthelight]

A hand pressurised sprayer struggles maintain the flow rate through a decent coverage fan jet.
You probably need a back pack sprayer with a pump operated by a side lever for the area you want to cover which are not cheap. I don't know if they can be hired.
Edit: Blimey, I didn't know they could be bought so cheap, the ones I have were 4 times the price or more.
"BS1 White Backpack Pressure Sprayer 12Ltr | Garden Sprayers | Screwfix.com" https://www.screwfix.com/p/bs1-whit...RlRhXnmLxL-zA1dW7_oaArNNEALw_wcB&gclsrc=aw.ds

 

[MisterBoy]

With mine, pumping it back up doesn't get the same appear which makes me think it's something else... But yes that's I might say suspiciously cheap. I was looking today and the low end ones were £80... Pro models double that.
Guess there's a big difference spraying loads of weeds in your drive, and guaranteeing a smooth even delivery to your lawn where you risk killing it and can't really have a second go?

 

[Stivino]

I had a similar problem with a sprayer, the control valve was full of crud. I stripped down and cleaned the whole delivery system and that cured it. It was as if the weedkiller had crystalised in the valve and little bits were getting stuck in the jet.