18 replies to this topic

[Dusky]

It's a combination of 2 things.
A:thickness of the needle versus the jet
B: the amount of air passing over the jet,drawing fuel out.
If you restrict the air flow with a thick oil you LL create a bigger vacuum at the jet. This only works during the half second you're opening the throttle and accelerating . It's a combination of the Bernoulli and venturi effect :)

[skoughi]

Piston stays down, only so much air can get in, engine is sucking like mad whilst it's spinning up so will draw in a little bit more fuel? As the piston rises then it's always playing catch up so there is always more fuel in relation to air? Or that's how I understand it!

[Chelsea_Pete]

Doesn't the float bowl cover use an o-ring seal?

Yes it does, I've added a gasket as a second line of defence although it doesn't seem to have stopped the leak, which returned after a drive about.

 

Good news is that overfilling the dashpot and letting it burn off has solved all my rough running issues. Ill have to try using a thinner oil next time and see which works best for me

[panky]

Glad it was a simple fix.

There is an overflow hole where the fuel hose connects to the top of the float chamber, it's hidden behind a little plate that fits over the stub and is held in place by three tabs bent around the casting where the stub goes in. If the float valve is passing then petrol could be seeping from the overflow and onto the top of the float chamber.

Edited by panky, 28 December 2016 - 07:21 PM.