I've just fitted a secondhand carb. It works fine, except there's a distinct reluctance to put power down at full throttle. Lift off a little and it picks up, but foot to the floor it's not as it should be. Anyone got any ideas about what it could be? Everything appears to be working but carburettor internals are something of a mystery to me. All advice gratefully recieved.

sounds like fuel starvation. have you tried jetting the carb? how clean are the internals compared to your old carb?

It all looks ok, I've just had the top off it and changed the accelerator pump, just to see if it makes a difference. off to work in ten minutes so I should know soon ...

Dirty jets me thinks - you need to clean out the one in the bottom of the left hand float chamber and also clean the aerator tube to the second choke - ssd

I reckon a dirty jet too, don't be afraid to fettle with a carb.....especialy if you have the old one, why not open that up first to give a feel the carb, then have a go at the new one.....it really isn't a black art, all you need is a clean tray, a nice selection of tools and a bit of spare time.....It is much better to familiarize yourself now than on the verge of an unlit road in the middle of nowhere at 2 in the morning.

Good luck,
Shane.

Cheers chaps. I'll clean out the jets tomorrow - well, today - because the new accelerator pump has made arse - all difference. I actually ran out of fuel tonight as well, prompting momentary thoughts that the problem had suddenly got much much worse.

RT
When you say "response at full throttle" do you mean accelerating from a wide throttle or is it just stuttery poor running at wide open throttle

if first then suspect the acc pump...but you did that

then its dirty jets
float heights
lid gasket
base gasket and manifold checks
( as well as timing, plugs and condenser)

and if you put on the new carb to solve the problem which is still there then have a look at the state of the rubber fuel pipe especially the one on the tank( since Kens off on a wander someones got to post that )

Sean

Sean,
it's only been a problem since I changed the carb. It slows down noticeably when you plant the throttle - doesn't exactly stutter, but it feels like it might - and picks up again when you lift off a little. 50 in third is no good, but 50 in 4th feels ok. Base gaskets are new (albeit homemade from gasket paper), float height is correct, manifold, plugs and condenser all worked fine with the old carb ... I'll just drink this coffee, then I'll go and blow the jets through.

Hmmmm. Blowing the jets through has made no difference either. It's actually worse than I thought: I came back from Wolverhampton down the M5/M50 last night and the thing struggled to go faster than 60 even on mild downhill stretches. The only thing I haven't checked (because I forgot) is the aerator tube betwen the chokes, but after that I really am stumped.

......and put the old carb back

what was wrong with it that it needed to be changed anyway?

the solex is a simple design with 2 moving parts(3 if you count the acc pump) there is very little to go wrong or wear out- SU's or a pair of them with needle wear, multiple positions and dashpots and diapragms .....thats a pain

biggest problem is people fiddling to "cure" ignition problems

i had a similar problem that stumped me till i put on a new coil and all was well

Sean