exhaust and choke...hum...

Post by **callyspoy** » Sun Nov 04, 2007 1:10 am

right, changed exhaust to 3 branch in preparation for upgrade to 1275, problem is the car now wont start. i dont want to believe that it is just because of back pressure(mainly because i cut the original exhaust in hlaf, whoops!) but i cant think what else it could be. i did try starting it with my foot partially covering the exhaust end so that it would cause more pressure, but still nothing. was tempted to think i may have flooded the engine...well...more hopeful...!
secondly...and slightly less pressing due to the circumstances...my choke cable doesnt stay out any more, so i assume the mechanism has knacked within the pull "switch". but...as its an early series II, the thing is brown, anyone know where i can get a brown choke cable??
cheers for your help, and rob jennings...the man with many questions has struck again! haha!
*Callum*

Post by **RogerRust** » Sun Nov 04, 2007 8:03 am

Trace back the actions you did 'till you find the one that caausing the problem.
for example
removed carb
removed old manifold
fitted new manifold
replace carb.

do you have an air leak?

Post by **bmcecosse** » Sun Nov 04, 2007 7:43 pm

If you have changed the exhaust manifold - then you will also have changed the inlet manifold - that's where the problem lies - nothing to do with exhaust 'back pressure' !!! So - what inlet are you using now? You need to tell us the full story - we can't play guessing games.

Post by **Peetee** » Sun Nov 04, 2007 9:38 pm

my choke cable doesnt stay out any more

Have you changed to an HIF carb? This requires a locking choke cable because the choke cam is sprung.

Post by **callyspoy** » Mon Nov 05, 2007 12:26 am

right...here goes...
Mr Rust sir...i have systematically gone over the car, not overly thoroughly as i've been quite busy, but i am off tomorrow, so can give it my undivided attention!
BMC...as much as your point is valid, my explanation was not thorough enough, your point came across more than rude. the inlet manifold is the same as the one i had on the car before as i had previously modified the original manifold so that i could run a different carb. the carb i have had on there worked fine before changing the exhaust, hence my feeling that it probably was not a carb issue, therefore me thinking that that is NOT where my problem lies. if you can offer help, as you regularly do, then please do.
PETE, no i do not have a hif carb. i believe that there is something in the toggle part of the choke that "catches" onto another bit, i believe one of these bits is missing...do you know where i can get a cable at all?? you seem to help me out quite a lot!!

Post by **downsey** » Mon Nov 05, 2007 3:17 am

my guess would be an intake leak, check the gaskets. Its a good idea to replace gaskets that have already been compressed.

Post by **Peetee** » Mon Nov 05, 2007 6:04 am

well i can furnish you with a 948 (black'ish fading to brown) choke cable no problem at all but I don't think that is entirely the problem. Have you checked that the manifold to head flanges are the same depth and both manifolds are tight up? Also, if the 3-branch is fouling the inlet (as they can do with some combinations) you would have a manifold leak at the head but it would appear to be tight up.

Post by **bmcecosse** » Mon Nov 05, 2007 7:31 pm

Callum - I consider myself 'down to earth' but not rude. How were we to guess you had already used a separate inlet manifold ? I do my best to help/advise - if you don't want it (and you seem to need it more than most) then just ignore. It stands to reason that if the engine ran before - and you changed manifolds etc - and now it doesn't go - the problem lies with something you have done. Your suggestion of 'exhaust back pressure' is non-sensible - it IS something to do with the fit of the new manifolds - or else it's something you have done while working on the manifolds. eg - Did you have the spark plug leads off - are they now back on correctly - in the correct order ? Anything else you have disturbed ?

Post by **leyther8008** » Tue Nov 06, 2007 9:07 am

I once did a manifold swap with one that I had store I,d taped over the holes to stop stuff and spiders going in and .... yep completely missed it when building the thing up

ran fine after I,d stripped it all down again and removed the tape, just shows how easy/stupid things happen.

Post by **Kevin** » Tue Nov 06, 2007 1:10 pm

I know you havent disturbed the ignition side but you do still have a spark and fuel, I have had unconnected problems occur before.