Technical No Idling (yellow racer)

[randomspeedfreak]

hi again guys,

ive got the yellow racer running (and all the electrics AND lights working ) however, although the top end of the rev range is fine, it wants to die below 3k, and spits and bangs and pops etc.

it definitely wont idle.

to start it you have to be on full throttle for a good 20 seconds until it (very slowly) climbs above 3krpm - above that it will rev very nicely and is perfectly fine.

ive just done the timing so i dont think its that, i think its mixture/carb related.

the regulator that is on the fuel line was set too high before so ive turned it down...would it be possible that the fuel pump could have broken one of the float chambers inside the carb by pumping too higher pressure in?

the bob springs ive just bodged back into where the originally were (i bent them by accident earlier on) im in the process of finding some new ones, but could it be them causing this problem?

anyone have any ideas?

thanks,
(almost very) Happy Matt

 

[randomspeedfreak]

just thought,

before i had set the timing it was spitting a bit back through the carb - could the pressure have upset the carb in some way?

any help much appreciated,
matt

 

[jjhepburn]

Do you know if the Uno ever idled properly? Some race cars coff and spit when idling, and only run properly when reving.

My Uno spits and backfires out of the carb from time to time. I've seen bursts of flame come out of carbs before.

 

[randomspeedfreak]

yeah it was idling fine before, about a month ago when it was last working. has just decided not to now

 

[alexGS]

Re-check the cam timing. Sounds like the belt is one or two teeth off?

It looks like you have a single carburettor, so that rules out a synchronisation problem - but you could easily just have a blocked idle jet. Take all the jets out and clean them - and while you have the top off, blow the carburettor out with compressed air. Also clean the float needle valve - if that's not coping with the fuel pressure, the carburettor would be flooding - you'd see petrol seeping out from around it.

Nice pic Who's that shady character in the background?

Also, those are classic Cromodora wheels that belong on my 124 Spider. They pre-date the Uno by at least ten years! You could probably raise good money by selling them on eBay

-Alex

 

[randomspeedfreak]

Re-check the cam timing. Sounds like the belt is one or two teeth off?

It looks like you have a single carburettor, so that rules out a synchronisation problem - but you could easily just have a blocked idle jet. Take all the jets out and clean them - and while you have the top off, blow the carburettor out with compressed air. Also clean the float needle valve - if that's not coping with the fuel pressure, the carburettor would be flooding - you'd see petrol seeping out from around it.

Nice pic Who's that shady character in the background?

Also, those are classic Cromodora wheels that belong on my 124 Spider. They pre-date the Uno by at least ten years! You could probably raise good money by selling them on eBay

-Alex

just incase it hasnt clicked for you, the car in question is the car mentioned here - https://www.fiatforum.com/uno/189329-bob-weight-springs.html (sorry if you ahve realised alredy)

sorry i should have been clearer, i set up the spark timing using your advice and the lumenition manual i found on the internet.

i dont think its the cam belt - it was fine last time i ran it and i havent moved the cam belt at all

im pretty certain its carb related so ill have a look and clean at the weekend as per your (as usual) excellent advice.

in the foreground is my mate louie - hes a petrol head on a similar scale to myself -He owns a pug 309 gti and jago jeep, soon to be swapped for a 1980s mosquito kit car!

background is Matt B - a general electrical wizard and chief instruction manual reader

haha! ive had a few questions about those butt ugly things
yeah i found out they're 124 based, they're magnesium too i think, they will be on ebay as soon as i can convince the old man to give me the MK1 strada 130TC wheels sitting in his shed!