Engine revs on its own?
Discussion
after finally getting my ignition and timing sorted i have encountered another problem with my spitfire 1500, its fitted with a single weber 45, this was fitted to go with some engine tuning that was done a good few years back. i have had the car for about 2 months now and its been running ok until recently.
the problem i have is after i start the car on the choke it will sit and idle fine, but as soon as the throttle is pressed it will rev and keep going, the throttle isn't open but it keeps accelerating. another issue i have is that it will only start on the choke, and even when its warm when i take the choke off it idles very low and sometimes cuts out. this obviously means that it has been resigned to the driveway, which is a shame in this weather.
any help is appreciated.
the problem i have is after i start the car on the choke it will sit and idle fine, but as soon as the throttle is pressed it will rev and keep going, the throttle isn't open but it keeps accelerating. another issue i have is that it will only start on the choke, and even when its warm when i take the choke off it idles very low and sometimes cuts out. this obviously means that it has been resigned to the driveway, which is a shame in this weather.
any help is appreciated.
yorkebar said:
its all in great condition as it was changed about 2 years ago, there dont seem to bbe any splits or cracks in the gasket or manifold.
When the car is running, grab a can of WD-40 and spray it towards the joints between the carb and the manifold, the manifold and the head, and the pipe to the vacuum servo (if fitted), and any other places where air might leak in. WD-40 is combustible, so if there is an air leak the engine speed will rise further as it gets sucked in. after taking the idle speed all the way down and then incramentaly taking it back up until the car started to run again i have solved the issue. its just odd that if i adjust it quarter of a turn more it revs on its own.... but all is well and the problem is solved. thanks for everyone's help as after checking the manifod gaskets i wasn't happy to find washers used as spacers as the exhaust and inlet manifolds are different thicknesses. time to buy some spacers....
RIGHT. here we go again. solved the revving issue. now i have it timed and tuned, the engine still misfires. below about 3000rpm its not smooth and sounds like its firing on 2 cylinders. then as soon as the revs rise its perfect again. making the car almost undriveable.
yet again, any suggestions.
my neighbor says it might be a blockage in my carburetor...
yet again, any suggestions.
my neighbor says it might be a blockage in my carburetor...
davepoth said:
When the car is running, grab a can of WD-40 and spray it towards the joints between the carb and the manifold, the manifold and the head, and the pipe to the vacuum servo (if fitted), and any other places where air might leak in. WD-40 is combustible, so if there is an air leak the engine speed will rise further as it gets sucked in.
As you say WD40 is combustable so best not to spray on a hot engine with spark ignition. WD40 is basicaly fish oil and aromatics,when atomised will ignite quite readily. Probably best to use soapy water ( or other non combustable substance), in an old kitchen cleaner spray bottle,as soon as the soapy water blocks the vacuum leak the RPM will change, this is the area to investigate.Edited by felixlighter on Thursday 16th August 20:20
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