Just started to strip, clean and rebuild my weber 40 IDF's I have the following set up 28mm venturies 3.5 auxillery venturies 3.5 pump jets F 11 emulsifiers 180 air 125 mains 50 Idle... Think they are the Idle jets. I know the mains, airs and emulsifiers are in the right ball park for my motor. Dose anyone have any knowledge on the pump jets and auxillery venturies?? Also float hight... Where to measure from and what hight Cheers simon Sent from my H8166 using Tapatalk
What are these? Are these what the air is sucked through when adjusting the air screws?... Which leads me on to my next question... How many turns out as ball park get me started setting? Cheers Simon Sent from my H8166 using Tapatalk
Ball park setting is flaps almost shut exposing just part of the first progression hole. Then I would wind the idle screws out 4 turns or so as it'll be starting from cold. It should idle cold with too much fuel so at least you'll be able to get round the back and adjust as it warms up. Once they are set and balanced, it will start easier from cold, but first time too much is better than too little fuel.
I wont be running round the back..too much i hope... Im bench starting.... Lol Sent from my H8166 using Tapatalk
Idle mixture screws one & a half turns out from lightly seated. Throttle stop screws half a turn in from hitting the plate lever is your starting base settings. Balance the carbs & set your mixture screws for best idle speed then slow down the idle by backing out the throttle stop screws evenly. Recheck balance. Throttle stop screws should not be more than 1/2 turn in as you start uncovering progression holes
The standard pump jets and auxiliary vents should be okay but with your cam and inlet valve size I think 28 vents are too small, the engine will run of course but it will be restricted at higher revs. For a bus engine many engine tuners will say the vents should be 4 to 6mm smaller than the valve size, I think that is too big but you’re around 14mm smaller than the valves, aren’t you? If you increase the vent size the idle jets might be a little small too. Float height should be 10mm from the face of the cover to the float with the cover held vertical and the float arm just touching the needle valve but not compressing the spring-loaded ball.
Will get some 30mm venturies Cheers for the help..this is what makes these sizes great...genuine tried and tested knowledge Simon. Sent from my H8166 using Tapatalk
I have a set of 30mm vents you could try but getting them from here to there would probably cost as much as buying new ones from the UK – or China.
Right... Ive stripped and cleaned my carbs...they are supposedly a matching pair... One carb has a set of 28 mm venturies and the other a set of 32 mm Lol. They came with some other spares but they were still on the manifolds with linkage... So must of been used on a running motor. Ive ordeded a set of 30mm venturies and some velocity stacks... So will have the carbs on next week sometime.... I hope Sent from my H8166 using Tapatalk
All jets, emulsifiers are correct...if they were all 28 i was going to open them openened up in my landlords lathe.... Just to add ive recieved my velocity stacks and have ordeded ones to suit a 44 mm idf... Ffs.. Should be back on track this week Sent from my H8166 using Tapatalk
