s.leah Posted January 14, 2015 Report Share Posted January 14, 2015 This may not be a problem.... I've not much experience with manual chokes! When I start my 13/60 (original engine/carb) on full choke it runs pretty rough. It chuggs and pops and sounds like it is miss-firing and threatens to stall if I so much as dare to push the choke in slightly. It's fine if I press the throttle the revs build up and it doesn't try to stall. After a couple of minutes when the engine is warm enough to run without choke, it runs beautifully so nothing basically wrong. Does this sound fairly normal or does my carb need a tweak? Cheers Simon Link to comment Share on other sites More sharing options...
Clive Posted January 14, 2015 Report Share Posted January 14, 2015 You just need to learn the foibles of a manual choke. However, it may need a tweek on the fast idle, check the manual for the settings. Link to comment Share on other sites More sharing options...
mishmosh Posted January 14, 2015 Report Share Posted January 14, 2015 Sounds normal ! Link to comment Share on other sites More sharing options...
Pete Lewis Posted January 14, 2015 Report Share Posted January 14, 2015 On full choke you need around 1500 rpm the first 1/2" should raise the idle to about 900 if the fast idle cam tappet is not opening enough it does what you have it becomes over rich and chokes itself to a lumpy stall set the tappet to give a small gap to its cam. pete Link to comment Share on other sites More sharing options...
s.leah Posted January 15, 2015 Author Report Share Posted January 15, 2015 I was a bit more scientific when I started this morning On full choke it was as described and it would rev OK. However, when I pulled away the power wasn't fantastic and although it wasn't warm enough to push the choke fully in, I did so as I drove down the road and there was a little boost of power as I pushed it in.. This leads me to think that it is probably as simple as fast idle not set correctly and I'm over compensating by pulling the choke fully out when I probably don't need to. Consequently it is running waaay too rich hence the lack of power under load. I suspect if I tweak the fast idle so it'll run with less choke (and eventually tweak so pulling it fully out doesn't over choke) all will be well Sorry for my waffling, I'm more thinking out loud... does my theory sound about right though? Link to comment Share on other sites More sharing options...
mishmosh Posted January 15, 2015 Report Share Posted January 15, 2015 Sounds reasonable. Give it a try. Link to comment Share on other sites More sharing options...
Pete Lewis Posted January 16, 2015 Report Share Posted January 16, 2015 pretty much all constant depression carbs be they stromberg or su need more fast idle than expected less than 2000 but more than 1000 or they choke to death on full choke. might make cold starts a bit brisky but soon caan be 'pushed in' as soon as initial warm up creeps in. the fast idle cams do wear and often the tappet screww gets a groove as this is hardly ever lubricated over the years you loose revs . make sure you nip the locking nut when re adjusted. this applies to the SU jet drop , stromberg Thames barrier , and the later side mounted starting valve chokes . Pete Link to comment Share on other sites More sharing options...
s.leah Posted January 16, 2015 Author Report Share Posted January 16, 2015 Thank folks As soon as it's warn enough that I don't risk my fingers snapping off, I'll have a tinker! Link to comment Share on other sites More sharing options...
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