Discussion
After setting the ignition timing with a strobe ( finding out I was only out by about 5 degrees retarded by guesswork. 
) Without driving, I could tell that throttle response was sharper and the engine just sounded better.
Then I remembered that I had never cleaned the fuel filter elements in the carbs, so took them both out (quite a lot of crap near the top part of the screens). Didn't drive it till today, started out by being hesitant on acceleration and generally missing irregularly under throttle.
After 20 miles or so get back home and it's even worse now, spluttering, popping, terrible.
Switch off engine, remove bonnet and clearly see fuel pissing out of both trumpets of the front carb.
Sticking float? blocked jet somewhere? Any procedure for this anyone?
PS it's a Lotus twin Cam.
Thanks.
) Without driving, I could tell that throttle response was sharper and the engine just sounded better.Then I remembered that I had never cleaned the fuel filter elements in the carbs, so took them both out (quite a lot of crap near the top part of the screens). Didn't drive it till today, started out by being hesitant on acceleration and generally missing irregularly under throttle.
After 20 miles or so get back home and it's even worse now, spluttering, popping, terrible.
Switch off engine, remove bonnet and clearly see fuel pissing out of both trumpets of the front carb.
Sticking float? blocked jet somewhere? Any procedure for this anyone?
PS it's a Lotus twin Cam.
Thanks.
its a needle valve fault and thats all that matters.
t must have been dislodged and got into the needle valve.Sorry for hijacking the thread but I wondered if someone could point out which is the idle mixture screw on a Weber 40 DCOE: 
Briefly, the problem is that I'm getting a misfire accelerating under load (Caterham xflow), although it's ok on a gentle throttle and at idle.
Might also be a timing problem (in which case I'll take it to the garage - turning a screw is about the limit of my mechanical abilities), but as the #2 plug is getting very sooted up I think it's running a too rich. As I'm planning on taking it to Le Mans on Wednesday I'm a bit miffed it's chosen now to start spluttering about the place but there you go!
Cheers,
Sid
Briefly, the problem is that I'm getting a misfire accelerating under load (Caterham xflow), although it's ok on a gentle throttle and at idle.
Might also be a timing problem (in which case I'll take it to the garage - turning a screw is about the limit of my mechanical abilities), but as the #2 plug is getting very sooted up I think it's running a too rich. As I'm planning on taking it to Le Mans on Wednesday I'm a bit miffed it's chosen now to start spluttering about the place but there you go!
Cheers,
Sid
King Sid said:
Sorry for hijacking the thread but I wondered if someone could point out which is the idle mixture screw on a Weber 40 DCOE:
Briefly, the problem is that I'm getting a misfire accelerating under load (Caterham xflow), although it's ok on a gentle throttle and at idle.
Might also be a timing problem (in which case I'll take it to the garage - turning a screw is about the limit of my mechanical abilities), but as the #2 plug is getting very sooted up I think it's running a too rich. As I'm planning on taking it to Le Mans on Wednesday I'm a bit miffed it's chosen now to start spluttering about the place but there you go!
Cheers,
Sid
See where the mounting holes are at the top,well there are two screws down those tubes attached to the side of said holes and they are for mixture control per choke a rough starting point would be 2.5 turns out from fully clockwise(dont tighten in hard)i found over the years the most common running problems on sidedraughts are air leaks and poorly balanced carbs then blocked jets and misinformed tinkering(not aimed at you)the important thing is make sure the mixture screws have equal turnsBriefly, the problem is that I'm getting a misfire accelerating under load (Caterham xflow), although it's ok on a gentle throttle and at idle.
Might also be a timing problem (in which case I'll take it to the garage - turning a screw is about the limit of my mechanical abilities), but as the #2 plug is getting very sooted up I think it's running a too rich. As I'm planning on taking it to Le Mans on Wednesday I'm a bit miffed it's chosen now to start spluttering about the place but there you go!
Cheers,
Sid
i miss my screaming X flow on 45,s 
Edited by That Daddy on Saturday 7th June 18:58
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