Rough running at low revs

dion321

Member
Hi all wondered if anyone can help Please, my 2200 tc has developed a rough idle smooths out when revved, fitted new plugs,dizzy cap rotor arm ,points condenser, and HT leads, checked timing then tuned carbs, revved smoothly thought job done, turned off, re-connected linkage put all back together same again? Rough revs trying to die but when revved smooths out? Any suggestions would be appreciated thanks.
 
In my experience rough running at idle is often caused by an air leak. Check the vac pipe from the front carb to the distributor and also the one from the manifold to the air cleaner flap valve.
If you've been playing with the carbs etc you could have dislodged one of them.
 
Thanks, checked all pipes fitted new coil, tickover a bit better but really bad when cold trying to cut out all the time, gonna check compression hope it's not valves. Thanks again.
 
Noticed that the thermo controlled unit in the air leaner housing is very loose, could this be the source of the cold running roughness or am I plucking at straws. Thanks in advance.
 
Remove the pipe to the aircleaner at the inlet manifold and plug it. This will rule out the flap switch. If the idle
Mixture is set too weak you'd get the same symptoms. Does It pickup if the choke is pulled out ? Another possibility is the vac advance diaphragm in the dizzy is Popped. Air will leak from the dizzy into the front carb.
 
Hi revs rise when choke pulled out and can set engine to fast idle with choke , sucked on pipe to dizzy and base plate moves as Spring stretches, will plug pope from air cleaner to inlet manifold and see what that does thanks
 
Pat180269 is spot on. Almost certain to be an air leak.

But there's a few more options for the source. Since the carbs are HIF's, the most obvious one is damaged O rings on the the throttle spindles. Not difficult to replace with the carbs off. The second obvious source is the arrangement for sealing the carbs to the manifold. They're flexibly mounted with a very peculiar sprung arrangement. Dismantle and check everything is as it should be. You really need to have the workshop manual and the parts manual to get what I'm on about there.....

Chris
 
Thanks for the advice will check everything borrowing a compression tester from a friend , to cover all suggestions thanks again.
 
You can check for airleaks in the areas Chris mentioned by spraying brake cleaner on the seals and listening for a change in the engine note.
 
Hi nipped a few things up seemed to tickover a bit better, checked compressions from front no.l 170. No.2. 170. No,3. 180. No4'. 140. Haven't checked valve clearences yet .
 
Everything checked valve clearences all ok, think it could be carbs issue?. Car has only done 61000 miles in 40 years, sometimes only 36 miles per year according to mot,s, I,ve also got a a 2200 tc with 109000 miles with no probs, Es to show using them pays off every time.
 
dion321 said:
checked compressions from front no.l 170. No.2. 170. No,3. 180. No4'. 140. Haven't checked valve clearences yet .

No4 is well down on the others, and that's not going to help with the running issues. Have you tried pulling the leads off one at a time to see just how much each cylinder is doing?
 
No but will tomorrow, thanks the 100 odd. Thousand car is as fit as a fiddle strange, but proves regular use pays off obviously. Thanx again
 
Yes no difference on all of them, the car was fitted with jets and needles before I bought it took a full day apparently??, will tick over and rev fine stood still, but on the move flat max 30 mph struggling and stalls all the time, thanks for your help.
 
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