Over-fuelling carbs

Sure you can borrow them , they are for my S/C project so they are wanted but I'm not at that stage yet . I have not used them but do have various size vents , jets etc

 

You won't get them back ...

 

Oh yes he will - (is it Xmas already!!) - what sort of condition they'll be in is another question though!!

I'm swapping my existing carbs from side to side this morning so that'll be interesting - don't want to start the bus too early in the morning for fear of upsetting neighbours but I've done the work and just a question of waiting til 0930 or so to test the results> Fingers crossed and most other things

 

Thanks a lot Steve - that could bring me an awful lot of 'peace of mind'!! I'm testing my side to side swap this morning so depending on results I may take you up on that offer

 

Did it work then?

 

Did it? ......... f f f flippin not. Well I suppose 'after a fashion' is the true answer. The fault stayed on the right hand side which seemed to eliminate the carb as the cause. However I thought I might as well swap the carbs back again but put a double gasket on the right hand carb cos I thought maybe air leaks? Started her up again and the f f f f f flippin fault was now on the left hand side. What the **** is going on here???? Any thoughts?

 

What are the symptoms of "the fault"?

 

Do you have a cracked/worn/loose distributor cap? Worn rotor?

 

See first entry Page 1 but summary was that carb was not functioning at idle, no adjustment on the mix screws would correct it but when open throttle on that one carb loads of black smoke. So, I guess either plugs not firing at low revs or idle mix problem. Now beginning to think ignition fault but why would it move from right cyls to left ones? Recently changed to a cheap electronic system so maybe ..................................?? However when I disconnect plug leads at dissie there are loads of sparks on all leads. So, maybe plugs or leads at fault?

 

Strange idea - what if it is slop in the distributor, engine fires one side, increases RPM slightly , timing changes for other side firing, cylinder misfires engine slows down again ?

Had something like this with the distributor not seating fully - timing bounced around .

 

Nope - checked for dizzie wear earlier but it's as snug as can be

 

Just changed spark plugs, cleaned up dizzie cap and rotor all to no avail. Might revert to points and condenser tomorrow to see if that makes a difference. Only other thought is an air leak but I reckon that would make a weak mixture not a rich one. Just don't know where to go from here apart from the ignition angle. Anyone any ideas?

 

I had a similar issue recently on my twin webers, thought I had an air leak but turned out that that the distributor was fooked. Had it swap out for a good second hand one works a treat now.

 

I have a dizzy you could also borrow ?...genuine refurbed Bosch on points

 

Steve - thanks very much - have pm'd you.

 

Swapped back to points and condenser this morning but no difference - left hand carb still not running at idle and after just a minute of the engine running the left hand carb is much colder than the right hand one and has moisture droplets on the outside body and on the butterflies - condensation!

Still haven't got a clue what's causing this - carbs (probably not as the fault has moved from right to left side), manifold leak (possibly??), pressure reg (prob not as delivers more fuel when pressure increased), ignition (plugs changed for new, electronic module swapped back to points), dissie (no side play on shaft, cap looks OK as does rotor).

Anyone got any more ideas / tests I can perform? What about a manifold leak - difficult to get spray all over both joints but wouldn't a leak cause weak mixture in cylinders?

 

the only probs like this i have experienced is with blocked idle jets , mine still got crap in them even with the banjo filters and a filter on the tank outlet . you could tell which idle jet it was as the manifold /exhaust was cooler than the rest @ idle . bound to be something simple

 

It still looks like it's running too rich, condensation on manifold and not idling properly on one side.

Did you say you've swapped the carbs from one side to the other and the problem stayed on the RHS? If so then maybe there's an issue with the fuel lines, maybe there's a 'restriction' on one side causing pressure on the opposite?

 

Yes, that's right but then when I swapped the carbs back again the prob moved to the other side!!! I have another IDF40 in the garage so I'm going to swap the dodgy one for the old one tomorrow and see what that does. Already thought about re-routing petrol supply lines or perhaps feeding just the carb on the dodgy side to see if it then works OK - another job for tomorrow methinks