Lads, if its pulsing it could be a couple of things, one being an air leak so if it has a chemical tank and the chemical mix is turned on, but the tank it empty then it will be sucking in air, so check that tehre is something in the tank, or the valve is closed. could also be a split hose so have a little look.

if its deffo not that then it most likely the seals. these are basically o rings!

there most likely be about 6 in total, 3 bigger seals on the pump head, and 3 smaller diameter but thicker piston seals.

whip the pump head off, about 8x 5mm cap head screws, pull pump head off, might need a tap to start it.

once the head is off there are probably 3 brass inserts, you will see the piston seals inside these, if they are damaged then thats your problem. very carefully prise them out the pump head without damaging them and remove the seals, take them to your local place that sells them, and they will probably be lees than a couple of quid, so buy double!

also check the pistons as some ceramic ones can crack, if they do then it may be difficult to get replacement ones but check the model number on google, you might be surprised!

yes, i used to repair pressure washers lol.

i myself have a sibitec, its 160bar and will tear you a new asshole lol.

but the gun has broke, it had water in it and it froze last year and cracked it apart!

i just need a new gun and lance, but for the price of that, i could buy a karcher lol

most washers pump design is quite similar, so half an hour with the spanners may save your a fair few £££££