Fast idle when warm

Hi, i just picked up a nice like 1986 90 with a 3.5 carb v8 standard, the idle at cold is normal, but when it warms up it idles around 2000 rpm! Its had a new dizzy cap and leads ect, i have checked for air leaks in the vacuum hose,
Any other ideas?
Cheers

Anyone??

Try adjusting the screw on the top of the linkage on the offside carb.

You can see it on the third picture of:-
Difflock :: View topic - Su Carb Id help

Directly up from the dish in the centre.

Seems to work on mine

Just tryd that, no change, its strange that its fine for 5-10 mins then when it heats up its idling at over 2000rpm

Is your choke adjusted correctly? That could
Be the cause

Yep, checked the choke too, its a manual one, and when pulled out makes it rev a little higher for a moment then splutters and dies out

To me it sounds like it's your choke, have you checked the adjustments on the carbs for the chokes. And the arrows all line up. I take it you got su carbs.

Yeah i have the su carbs, i have checked the choke and throttle linkages and its all returning fully. It sounds like an air leak but its only starting when warmed up. I cant find any holes in the vacuum hoses, i have sprayed wd40 on the motor, no change.
Very annoying!!!

Presume that u have tried adjusting the idle speed down when the engines hot and so can idle normally.
if u did then the cold start idle would be zero maybe but then the choke (manual or automatic) if adjusted correctly would give u an idle until the engine warms up and the choke can be pushed-in in your case.

Yeah, i unscrewed the fast idle screws right out but it made no chaange so i put them back where they were, wouldd the temp switch make it run fast when warm?

Going back to my carb days, the only temperature sensor/ switch was for the dash temp gauge, so no bearing on the running of the engine.

To save me getting my manuals out what other temp switch do u have?
Also as a thought do u have standard air filter/s fitted and not ones with with the emissions gubbins that were fitted to some engines in the past?

As far as i can see theres no other temp switches/sensors? And the airfilter is standard, what are the gubbins?

Could it be the timing? As its had a new dizzy cap ect on it?

sean82 said:

As far as i can see theres no other temp switches/sensors? And the airfilter is standard, what are the gubbins?

Click to expand...

Various emission items that work via bi-metal and vacuum controlled valves and are now always done away with, as they never worked and caused problems.

Could it be the timing not unless it's been altered.

Have you taken off the throttle link bar that connects the two carbs together?

And then in unscrew each idle screw.

Where abouts are you from??

Il give that a go, cheers. Im from guernsey mate.

Shame your not local to me as I would have had a look at your carbs.

Which idle screws have you been adjusting. There's three idle screws.

There's the one common one on the throttle link bar, and there's one on each carb.

And each carb has a choke adjuster too with a link bar that needs adjusting too.

Its the one highest on the carb i have been adjusting.
Cheers for the offer, most kind of you sir!

Sounds like your carbs need a full set up to be honest.

that screw you've been adjusting is the very last step if you can't slow it down with that then they need to be fully setup.

it's not to hard to do but you need a carb balancer and you need to do step by step.

I can get a carb balancer, is there any guides to setting the carbs up about?