High Revs and engine run on

[jules42]

Hope you can help!!! On the way home tonight all running fine and pushed in choke, when came to the lights and stopped the revs were still quite high but the choke was pushed in all the way, around 1500 but it has been difficult to get the choke completely off the last couple of times. So I thought to pull the choke out and then push back in - that was not the best idea!! the revs went up to 3K and stayed there even when the choke was pushed in all the way. I only had a further 5 or so miles to go so just got her home. Interesting when going slowly (or trying to go slowly) as hardly needed any throttle in fact could have done with out it!!
When I got home and turned her off she must have run on for at least 5 seconds - thinking that was the excess petrol.

I thought that it would be that the choke was stuck on but when the bonnet was put up it seems not checked that both sides were in the "off" position - I started her up again and the revs were straight up to 3k again.

After letting the car cool down (and having tea) have been back out just to double check that the choke wasn't stuck on and it is definitely off. Started the car again and engine fairly cold started with no choke and sat at 2k. Also noted - may not be linked but the top hose from the radiator to the water pump was sucked almost flat.


Any ideas?

[Bob Heritage]

Probably 2 unrelated problems, Has the excess length on the choke cable fouled the throttle linkage? happened to me once and I took a roundabout about 60mph, severe earache followed

[jules42]

Hi Bob,

Dont think that the choke cable has caught on anything it all looks as "normal". Have to say it is "interesting" as you say when driving with high revs!!

Any other ideas or what else to check - could really do with getting this sorted before sunday as want to take the car to a silver wedding party

[martin]

Hi Jules, the throttle cable could have become unseated, make sure it's all the way into its ferrule and not hooked on the edge. Is your car an auto? it's also possible the kick down cable may be involved. Martin.

[bunny]

HI
With looking its diff to know but if you link the hose and revs together you have to look at the inlet manifold plus dashpots, maybe
vince

[jules42]

Hi Martin,

Car is manual not auto, will check the throttle cables again tomorrow and the choke, its strange it just happened on the way home as the car was running fine until I pulled the choke out to try and get it back in again. Its difficult to know if the throttle is not fully closed as not sure how that would look as not taken any notice before!!

Thanks
Jules

[martin]

Hi, it's probably worth disconnecting both choke cables, and both throttle rods when the engine's warm to isolate the problem, if the idle returns to normal you've found it. It's a fairly steep learning curve if you're not familiar with these carbs, so if nothing obvious turns up, you could do with some help. Are you in touch with the Leicester group ? If not, I'm only a bit south of Market Harborough if you care to pop down. Before you start her up again, check your coolant level, first in the radiator, then replace the plug after topping up, and remove the pressure cap from the expansion bottle and make sure it's about one third full Martin.

[ChasR]

I am going to go along with Bob Heritage's idea here that there are a few problems present.

What is your ignition timing like? I would also go with Martin's idea of disconnecting the rods and cables and going from there.

[V Mad]

The engine can only rev to 3000 if the throttle valves are open (or the overrun 'poppet' valves have failed if fitted that is). The fast idle cam on the LH carb often gets stuck 'on' even if the choke cable is pushed fully in and the cable is released so this could be the cause. If the cam is clear of the fast idle lever screw (not touching) then one of the link rods that control throttles may have dislodged, or as other have said throttle cable jumped out of place and holding throttles open.

To get back to idle speed try disconnecting throttle link rods. If that doesnt do it maybe you have failed overrun valves in the throttle butterflies?

[jules42]

Hi Chris,

Thanks - all very new to this so will get books and pics to see where all the bits are you have mentioned and check each of them out

Martin - we do go the the leicester and warwickshire meetings but as most of our group are going to the AGM didn't want to disturb and as I use the forum a lot to find answers to problems or queries and as there didn't seem to be anything on about this already I thought it would be good to post so it may help other newbies like me in the future. Coffee and then out to the garage to take a look!!

[martin]

Hiya, posting is good ! I just meant, have you access to hands on help ?