adam73bgt
Club Retro Rides Member
Posts: 4,868
Club RR Member Number: 58
Member is Online
|
|
Sept 28, 2012 9:21:10 GMT
|
Bit of an interesting issue here.. Basically while i was driving up the a14 to uni, it soon became apparent that when depressing the clutch to change gear, the engine was revving up... so yeah basically the throttle has suddenly decided that it no longer wants to return to zero which is irritating to say the least... and also made driving round town in coventry quite an experience  I think the issue is where the throttle cable comes through the bulkhead next to the pedal box as here theres a sort of bell shaped bit of metal which i assume used to secure the cable to the bulkhead but theres a lot of filler or some substance here and its not particularly secure   sorry the pictures arent the greatest quality, its not the easiest bit to photograph right up in the corner of the engine bay.. so basically I'm asking if anyone has had this issue before or has any advice so i could do a fix myself  (or could do the work themselves for some monies  ) oh and also the accelerator pedal has always not had much travel, it seems to hang down too far, like if you pull on it theres the potential for about the double the travel it currently has.. so perhaps the accelerator has always been badly set up or something?... any help is greatly appreciated! thanks in advance |
| |
|
|
|
|
|
|
|
Sept 28, 2012 11:36:21 GMT
|
|
I cured my 'involuntary mechanical cruise control' by simply disconnecting the cable at the carb injection pump end, holding it up and feeding a load thin oil down it with lots of wiggling of the cable as I did so.
When you push the pedal to the fullest extent of its travel, is there still more movement available on the carb?
|
| |
...proper medallion man chest wig motoring. |
|
|
|
|
Sept 28, 2012 12:59:56 GMT
|
This might sound blindingly obvious but have you checked that the throttle return springs on the carb linkage are still connected? |
| |
Old Fords never die they just go sideways
|
|
Mike
Part of things
Posts: 352
|
|
Sept 28, 2012 13:12:04 GMT
|
|
2nd the return spring...nightmare. also...have you taken the carbs off lately? i managed to get the linkage beacktofront or upside down or something and had the same problem. failing that oil it or get a new cable i had a mate who had a frayed cable and that stopped it returning as it should
|
| |
|
|
adam73bgt
Club Retro Rides Member
Posts: 4,868
Club RR Member Number: 58
Member is Online
|
|
Sept 28, 2012 13:15:24 GMT
|
just went to double check and there is a lot of extra movement usually at idle the lever in the middle of the carb linkage is restrained by the choke linkage, recently (since it started its involuntary cruise control) though its been sitting slightly below the linkage like this  sorry thats a pretty bad photo to illustrate it.. lol on 'full throttle' or rather with the pedal on the stop, it looks like this   so yeah theres a fair bit to go before the throttle cam hits the stop.. that did sound obvious cortinaman, but i still hadnt fully checked it! haha but I'm glad you mentioned it because on closer inspection it appears that while the central spring and rear carb spring are still connected to the manifold heat shield, the front carb spring isn't. you can just about see it on this photo  |
| |
|
|
adam73bgt
Club Retro Rides Member
Posts: 4,868
Club RR Member Number: 58
Member is Online
|
|
Sept 28, 2012 13:21:32 GMT
|
although when moving the throttle by hand the front carb still seems to behave like it should?.. ill definitely try and get the spring back on properly when its stopped raining though |
| |
|
|
adam73bgt
Club Retro Rides Member
Posts: 4,868
Club RR Member Number: 58
Member is Online
|
|
Sept 28, 2012 13:23:36 GMT
|
|
oh and the carbs havent been off while ive had it but the throttle cable seems to be really badly adjusted, so someone might have had a go at some point...
|
| |
|
|
sonus
Europe
Posts: 1,386
|
|
Sept 28, 2012 16:13:01 GMT
|
Looks to me that there is excessive friction in the SU spindles or the cable is stiff in its housing Have you tried moving the butterfly shaft/spindle by hand? this might also help www.mgexperience.net/phorum/read.php?1,1665293,1665293#msg-1665293 Edit: I replaced my throttle cable with a bicycle brake cable and housing. Work a dream and a lot easier to come by than MG bits. |
| |
Last Edit: Sept 28, 2012 16:14:08 GMT by sonus
Current
1968 TVR VIXEN S1 V8 Prototype
2004 TVR T350C
2017 BMW 340i
Previous
BMW 325d E91LCI - sold
Alfa Romeo GTV - sold
Citroen AX GT - at the breakers
Ford Puma 1.7 - sold
Volvo V50 2.0d - sold
MGB GT - wrecked by fire
MG ZT 1.8T - sold
VW E-golf Electric - sold
Mini Countryman 1.6D -sold
Land Rover Discovery TD5 - sold
|
|
Seth
South East
MorrisOxford TriumphMirald HillmanMinx BorgwardIsabellaCombi
Posts: 15,515
|
|
Sept 28, 2012 16:26:09 GMT
|
|
Well, something must be up with the cable/pedal end seeing as you're only getting about 1/2 throttle. Should be a bit faster once you sort it out.
What's going on with your choke cable attachment too? Looks like a rather Heath Robinson affair.
|
| |
Follow your dreams or you might as well be a vegetable. |
|
adam73bgt
Club Retro Rides Member
Posts: 4,868
Club RR Member Number: 58
Member is Online
|
|
Sept 28, 2012 16:48:15 GMT
|
yeah ive moved the throttle linkage by hand and it feels ok to me, i think the throttle cable has just been really poorly set up ha ill be looking forward to some more speed in that case, ive always assumed that it was going as fast as it could, but then it struggles to break 80mph lol not that i would do that on a public road anyway....  erm as for the choke cable, the bracket its attached to is an original part apparently, its held on by the bolts that hold the air filters to the carb, the actual connector holding the cable there looks like its probably seen better days but the choke works fine, if rather stiff to use |
| |
|
|
|
|
bl1300
Posted a lot
Posts: 1,678
|
|
Sept 28, 2012 18:05:32 GMT
|
|
Have you checked that the engine earth strap is good it is not unheard off for engines to earth through throttle cables and melt the outer cable, causing the throttle to stick.
|
| |
Current fleet.
1967 DAF 44
1974 VW Beetle 1303s
1975 Triumph Spitfire MkIV
1988 VW LT45 Beavertail
1998 Volvo V70 2.5
1959 Fordson Dexta
|
|
sonus
Europe
Posts: 1,386
|
|
Sept 28, 2012 20:16:24 GMT
|
is this pic with the butterflies closed If so your linkage is incorrectly fitted. The opposite part of the L to where the cable attaches to is supposed to be up under the choke shaft. If this is the closed position the cable won't be able to rotate the shaft enough before the arm is at its closest to the cable stop. Loosen the pinch nuts rotat the arm downward until the opposite side sits touching the underside of the choke shaft, Retighten the throttle cable to the arm - voila |
| |
Current
1968 TVR VIXEN S1 V8 Prototype
2004 TVR T350C
2017 BMW 340i
Previous
BMW 325d E91LCI - sold
Alfa Romeo GTV - sold
Citroen AX GT - at the breakers
Ford Puma 1.7 - sold
Volvo V50 2.0d - sold
MGB GT - wrecked by fire
MG ZT 1.8T - sold
VW E-golf Electric - sold
Mini Countryman 1.6D -sold
Land Rover Discovery TD5 - sold
|
|
adam73bgt
Club Retro Rides Member
Posts: 4,868
Club RR Member Number: 58
Member is Online
|
|
Sept 29, 2012 2:06:45 GMT
|
nah that was with my toolbox holding the accelerator pedal on 'full throttle', usually the L piece is pretty much resting on the choke linkage at idle, though recently it has sat slightly lower than the choke linkage (by a couple of mm) which would link in with the idle speed being about 2500-3000 rpm..  |
| |
|
|
sonus
Europe
Posts: 1,386
|
|
Sept 29, 2012 13:43:41 GMT
|
|
is "full trhottle" with the accelerator pedal sitting against the pedal stop?
|
| |
Current
1968 TVR VIXEN S1 V8 Prototype
2004 TVR T350C
2017 BMW 340i
Previous
BMW 325d E91LCI - sold
Alfa Romeo GTV - sold
Citroen AX GT - at the breakers
Ford Puma 1.7 - sold
Volvo V50 2.0d - sold
MGB GT - wrecked by fire
MG ZT 1.8T - sold
VW E-golf Electric - sold
Mini Countryman 1.6D -sold
Land Rover Discovery TD5 - sold
|
|
adam73bgt
Club Retro Rides Member
Posts: 4,868
Club RR Member Number: 58
Member is Online
|
|
Sept 29, 2012 13:52:00 GMT
|
yeah, but in reality, because the cable is poorly adjusted it looks like its only about half throttle at the carbs.. ive partly fixed this now, anyone who thought it was the throttle return spring was correct! heres what the old one looked like  only had one hook left on it lol sorted it for the moment by nicking the spring for the choke return  started it up and it was idling back down around 850rpm as it should be, still has a slight issue with an inability to rev at all from cold but thats another story... just need to adjust the throttle cable to give me proper travel and it should be a lot better |
| |
|
|
ChasR
RR Helper
motivation
Posts: 10,194
Club RR Member Number: 170
|
|
Sept 29, 2012 14:06:42 GMT
|
I was going to say, the throttle spring sounds like a likely culprit Glad you got it sorted. If you are in Cov and need a hand with setting the carbs up (or ignition timing if you don't have a strobe light) let me know . |
| |
|
|
adam73bgt
Club Retro Rides Member
Posts: 4,868
Club RR Member Number: 58
Member is Online
|
|
Sept 29, 2012 14:21:49 GMT
|
aye, don't know why i didnt think of it earlier to be honest, ah thanks for that, the timing should be fine as it was done when i got the accuspark fitted but if i reach a dead end with fiddling with the carbs to get it running better from cold, ill give ya a shout |
| |
|
|
(or could do the work themselves for some monies 
)
