viewtopic.php?t=41411&sid=781db5c56e012 ... 37f41d6ef7
I'd personally persevere with the PWK, but although they are great carburettors, they rely entirely on the Lambretta OEM type fuel filter which should always be augmented by an inline filter. If you haven't already done so, it is essential to blueprint the PWK with regard to float setting/orifice checking & if you investigate on-line, you will find other modifications worth doing. The float stops in the bowl are best removed & the bowl drain plug hole can be cut back to allow replacement of the pilot without having to remove the bowl itself.
However, whichever carburettor is chosen, I tend to take for granted that the starting point to be applied is an adequate pilot jet. Plug readings (even if it doesn't start) will soon show a wet or dry plug
Unfortunately, the pilot & choke being the smallest of the jets, they are the first to be affected by any sort of blockage/flow problems due to the very fine sediment that can get through to the bowl. It doesn't necessarily completely block the pilot as the vibration - once the engine is running - tends to clear a partial blockage. Petroil mix needs to be fresh, particularly with ethanol in it these days & a modification worth applying is to fit a miniature drain valve to the float bowl screw which runs off any bowl fuel via some tubing to a catch tank/cup/jug when necessary. it saves a lot of mess & money when jetting in a 'new' engine set-up...... As a matter of interest, what are the jetting details that you have tried with both carburettors? My guestimate - presuming that the engine is piston ported - would be for the pilots:
Dell'Orto: 50ish
PWK: 32ish
However, it would be best that you Posted the complete slide/MJ/PJ/atomiser/choke/float bowl 'jetting' details where applicable for the carburettors that you have tried & confirm piston ported or reed for any intelligent diagnosis to be made.....
