matt_k Posted February 12, 2011 Share Posted February 12, 2011 I have a walbro 8 carb, there is two visible adjustments one cone shaped and one longer and straight. Reading on the miniplane manual it says the long adjustment is for idle mixture and the cone one is just a throttle stop. So what will adjust the mixture at high rpm if running too lean? Quote Link to comment Share on other sites More sharing options...
clivefreeman Posted February 12, 2011 Share Posted February 12, 2011 Mat i think you will find that you dont need to adjust for top end as it adjusts itself. (Kinda Auto if you like ) You only adjust for low rpm. And the cone shaped one is for idle. Thats the beauty of the w8 carb, very easy to adjust. Im pretty sure im right on this. Thanks Clive Quote Link to comment Share on other sites More sharing options...
cobra Posted February 12, 2011 Share Posted February 12, 2011 I think on this carb the adjuster is for bottom end and the top end is set by an internal jet so not adjustable unless you changed the jet of course, bit like a motor bike Quote Link to comment Share on other sites More sharing options...
lukebanks1 Posted February 13, 2011 Share Posted February 13, 2011 The WG8 carb has a fixed high rpm jet (non adjustable) The long slender screw adjusts carburation up to around 50% max rpm. The conical screw adjusts the idle by adjusting where the throttle lever stops and therfore the position of the butterfly in the carb. There's loads of info on the TOP 80 yahoo group. If its running lean there is a problem elsewhere! You'll be able to tell if you need to adjust the long slender screw as the engine won't pick up nicely from idle if fuel is restricted at this range. Regards, Luke Quote Link to comment Share on other sites More sharing options...
fanman Posted February 15, 2011 Share Posted February 15, 2011 Luke's advice is spot on. If you are running lean at top end on a WG8 then the only likely reason is air either getting into the fuel system (most likely) or leaking into the crankcase. Quote Link to comment Share on other sites More sharing options...
weesplat Posted February 15, 2011 Share Posted February 15, 2011 Or a partialy blocked main jet Col... Quote Link to comment Share on other sites More sharing options...
dantheman Posted February 15, 2011 Share Posted February 15, 2011 Ages ago I had to adjust the meter lever (bend it up a bit) on my WG8 to richen the mixture, works a treat now Quote Link to comment Share on other sites More sharing options...
fanman Posted February 16, 2011 Share Posted February 16, 2011 Unless you have removed the screen in the pump side of the carb then a Walbro is not likely to suffer from a blocked main jet. It is worth back flushing (or better still replacing) this screen though. Bending the lever arm is a possibility if priming by manually depressing it through its orifice. Check the height with the very cheap tool from Rowena. If it is correct then look for air leaks in the fuel system as mentioned. Quote Link to comment Share on other sites More sharing options...
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