For decades, I have just try to blow thru it & press the needle with light finger pressure & if it blocks, I assume its OK.

Over time I've sometimes noticed a bit of fuel dripping from the throttle spindle & a slight difficulty starting from hot. Didn't pay much attention.

Last week, in the bush, I parked overnight on an up slope with a full tank.
I got home to fumes from the engine & found a lovely halo of oil spray on the inside of the engine lid (KG)

The fuel had leaked into the sump & thinned out the oil so much that it defeated the oil return scroll on the fan pulley!

Oil change fixed the proplem- hopefully no damage to bearing & barrells!

Wot's the go with needle & seats? I'm tempted to rig up a carby in the vice & leave a old m/cycle tank of fuel connected to it o'nite with gravity feed to see if it leaks!
Or do ppl just replace them regularly?

If you have an older VW with a fuel tap, it may be an idea to turn it OFF when parked uphill to make sure.
Funny, but until recently, all m/cycles had fuel taps that you turned off when parked. That's a habit I always follow when parking my old BMW R100RS as a matter of course. Is there a lesson there?

I always have replaced the needle and seat
whenever I had a leakage problem..

it usually fixes the problem...

it doesn't take much for the N&S to leak...

do you have a good fuel filter on the fuel line?

its also much cheaper than a new motor.... lol

cheers

Lee

Pull a vacuum on the inlet side and let gravity pull on the needle [with your mouth will do] When the vac is good , seal it and it will hold the needle. If it drops you got a leaking needle or seat. New does not mean good. Sometimes you can lap the needle to get a good seal [car polish willdo].

Matberry, thank you! Nothing like lateral thinking is there! That eliminates the problem of over compensating by pushing on the needle with a finger much harder than the float could possibly do it. I apply a similar principle to bleeding brakes: rather than pumping the master cylinder, I suck fluid out of each bleeder nipple with a disposable 60ml syringe. It also makes it a one man job!

Lee u r right; they cost peanuts anyway!