I bought a pressure washer recently for a tenner. Built by Flexian in the early 1980's, it is powered by a 250cc Honda 6.5 hp engine. This drives a four piston pump delivering something in the order of 2,500PSI.
The engine had no compression and had obviously been stood about for a l-o-n-g time.The way it huffed made me think there was a (side) valve stuck open.
Four bolts detached it from its trolley & it was soon cleaned with Gunk (not the stuff of my youth, unfortunately ;o(( ) and the petrol tank, shrouds, recoil starter, carb, exhaust, head and tappet cover were soon off. The exhaust valve was stuck open but quickly succummed to a bit of poking, prodding and lubrication. I was surprised to find that both valves seated properly & didn't allow any of the Plus Gas I dropped on their little heads to leak through the seats. The cylinder bore was a fine, dull grey, used but obviously OK. I decided to leave well enough alone, Hylomared the intact fibre head gasket & rebuilt the engine.
The Keihin carb was stripped & cleaned & found to be minus its float needle, but a quick look in my old bike carb junk box turned up an identical valve in a Honda CB175 carb, so it wasn't the problem it could have been.
I stripped the tank & cleaned out the ancient residue of petrol from inside using my favourite method of a (counted) handful of nuts & bolts & a pint of paraffin. It was a manky, rusty mess inside & out, so I whipped the remaining paint off the tank, primered it & found one of my tins of spray paint (I bought fifty odd for £20 from a motor factor a while ago) matched the Honda colour very well. Whilst I was at it, I did a rough paint job on the fan covers which were poor but not that desperate, finding a good match for the red in my box, too!
The engine was brass wire cup brushed & lacquered & the whole assembled. And very nice it looks too.
Of course, it didn't start straight off. Someone had "readjusted" the float height & the carb wouldn't fill, but that was readily solved & away it went.
Takes a lot longer to do than write, dunnit?
The pump is a beast of a thing, the pistons being operated by a "crankshaft" of eccentrics that push their pistons into rubber diaphragms. I look forward to seeing if it needs stripping down ..........