TR6 Sticking TR6 throttle

bcbennett · Apr 10, 2011

Hello All,

I had my carbs rebuilt at a reputable British shop. Upon driving home, I noted that my throttle would frequently stick when I took my foot off the pedal, and I would have to "pop" it to get it to come back. Sometimes, it would just rev higher and not return until I repeated the "pop." Very annoying.

When I returned it to the shop, the tech said he lubricated the linkages and it was now fixed. Driving home the second time, I noticed it was NOT fixed. Still sticks open, especially when driving around 60 mph (almost like having cruise control). Any ideas here? Do I need to just further lubricate whatever he lubricated at the shop? There seem to be no impediments to the smooth functioning of the accelerator linkages.

Thanks in advance,

CB

tdskip · Apr 10, 2011

Could be an alignment of the linkage. When they are very dry or dirty sometime you'll get a reluctant throttle, but I doubt this is the case here given that you drive/care about here.

Have you checked that the springs are all still attached correctly?

M_Pied_Lourd · Apr 10, 2011

CB,

Here is one suggestion. Open the bonnet and operate the linkage by hand. See if it might be binding on the heater hoses that run from the bulkhead to the hose connection at the rear of the block. You may find that the mechanism is rubbing against this hose. I used a zip tie to tie mine back a little bit to stop the interference.

Cheers,
Tush

bcbennett · Apr 10, 2011

Thanks for these suggestions; I have verified that the linkage is not binding up on any hoses, clamps, or other items, plus I have assured myself that the springs still operate properly. I am at a standstill here.

poolboy · Apr 10, 2011

I had a similar problem when I changed the throttle shaft bushings.
They were a little tight around the throttle shaft and that friction prevented the return to idle speed.
I sat behind the wheel and with the engine NOT RUNNING, of course, and worked the accelerator pedal about a hundred times until the bushings "broke in" and the shaft moved freely.
Were the bushings replaced ?

trrdster2000 · Apr 10, 2011

BC, Your mechanic was very silly to let you leave with a sticking peddle. I think you may have a off center butterfly or linkage adjustment that is too tight.

Wayne

bcbennett · Apr 10, 2011

Well, honestly, my mechanic didn't know because it only sticks when I drive in highway mode--getting it up to 60 mph--or else when it's been driving a while and then I rev it past 2000 rpms (when starting or upshifting). When going through low gears and/or starting from cold, it does not do this.

Very weird, no?

TR3TR6 · Apr 10, 2011

CB:

I had the same problem with my 76 TR6. What I noticed was that it seemed to stick more after the engine was warmed up. I finally put a stronger return spring on the linkage and that took care of it. Good luck.

Brosky · Apr 10, 2011

He should have road tested the car and worked this out before you picked it up. You can lube the mechanical linkage and check the throttle shaft alignment, but in my opinion the mechanic should make this right for you at no charge.

bcbennett · Apr 10, 2011

OK, I think I have found the problem, but am not sure how to fix it.

The cam that holds the "fast idle screw" is hanging up against the piece of the carb that holds the "idle screw." That is, when the throttle is pressed, these two parts both move and one hangs on the other. How can this happen?

tdskip · Apr 10, 2011

poolboy · Apr 11, 2011

The fast idle cam should not move at all with the accelerator pedal.
I wonder if there's been a return spring installed on the choke shaft amd wound in the wrong direction.
If not..
Is the fast idle speed adjustment screw in proper adjustment ?
Is the choke cable adjusted correctly so that the choke is completely off when you push the knob ?

bcbennett · Apr 11, 2011

Well, this is sideways (sorry) but it shows the two parts that hang up. One is the cam with the fast-idle screw, the other is the top-seated idle screw.

Are you saying the piece holding the fast-idle screw should not move with the accelerator?

poolboy · Apr 11, 2011

No, I was saying the fast idle cam that is controlled by the choke cable, which is not even in that picture, should not move except when you pull or push the choke knob on the dash. Where is it ? Seems like a portion of it would have shown up in that picture.
Regardless, I think the cause of the hang up is that your idle speed (aka throttle stop) screw (the one with the rusty head) is screwed so far in that it's hanging up on the platform upon which it normally rest at idle.
It looks as though the screw is tightened to the point where the spring around it is almost fully compressed.
You shouldn't have to that much threads showing to get an idle speed under 1000.

DNK · Apr 11, 2011

After Ken has just said. With that pic in mind. I agree and I don't know dungus about carbs. I'd say something is FUBAR and they are trying to circumvent the problem

tdskip · Apr 11, 2011

Agree with Ken and Don.

How about a couple pictures of the carbs in the right orientation?

TR3driver · Apr 12, 2011

Nelson's photo shows that spring mostly compressed, and I think I can see just a bit of daylight in CB's photo above. So I'm not convinced there is a problem with the idle adjustment.

One question, how did you verify that the binding was at that joint? Does it go away if you hold the vent lever (the one that carries the adjustment screw) in the idle position?

Have you tried smearing just a bit of grease in the contact area? Smoothing the end of the screw?

TR3driver · Apr 12, 2011

Nelson's photo shows that spring mostly compressed, and I think I can see just a bit of daylight in CB's photo above. So I'm not convinced there is a problem with the idle adjustment.

One question, how did you verify that the binding was at that joint? Does it go away if you hold the vent lever (the one that carries the adjustment screw) in the idle position?

Have you tried smearing just a bit of grease in the contact area? Smoothing the end of the screw?

bcbennett · Apr 12, 2011

I can physically see that junction catching and holding things up as I move the linkage under the hood, and yes, if I hold the vent lever, things do not bind. It never did this until I had the carbs rebuilt, so I think something must be different in the set-up.

poolboy · Apr 12, 2011

tdskip said:
Agree with Ken and Don.

How about a couple pictures of the carbs in the right orientation?

I wouldn't mind seeing another picture myself, one where a bit more of the carb can be seen, particularly the choke assembly and the plunger for float chamber vent.
Seeing the shiny freshly exposed threads on the throttle stop (idle speed) screw and the fast idle speed screw seems the adjustments are now quite different from what they used to be.

Thread starter	Title	Forum	Replies	Date
	TR6 TR6 door bottom sticking out	Triumph	2	Aug 14, 2006
	TR6 Sticking TR6 Clutch	Triumph	15	Nov 11, 2005
K	TR2/3/3A Sticking front brakes?	Triumph	9	Sep 20, 2021
F	Choke sticking	Austin Healey	22	Oct 23, 2018
	"Sticking" the brake pedal	Austin Healey	3	Oct 1, 2018
K	TR2/3/3A Oil pressure gauge needle sticking?	Triumph	4	May 16, 2017
T	TR2/3/3A Sticking Clutch	Triumph	6	Aug 30, 2016
	TR2/3/3A Overdrive solenoid sticking	Triumph	6	Feb 13, 2016
T	throttle sticking?	Austin Healey	4	Mar 13, 2015
T	TR4/4A Overdrive piston is sticking	Triumph	9	Nov 19, 2014
K	TR2/3/3A Oil pressure gauge indicator needle sticking?	Triumph	10	Jul 15, 2014
B	Sticking Starter Pinion	Austin Healey	6	Mar 28, 2014
M	Sticking speedometer needle	Triumph	2	Feb 9, 2013
J	Oilcan spot on fender [IE: not flat, sticking out	Triumph	2	Nov 26, 2012
J	STICKING THROTTLE PLATES	Jaguar	7	Aug 24, 2012
	H6 carbs -jets sticking	Triumph	15	Aug 18, 2012
M	Front brakes are sticking	Spridgets	33	May 28, 2012
	TR2/3/3A sticking clutch ??? TR3	Triumph	5	Mar 31, 2012
M	Sticking M/C piston	Triumph	7	Sep 12, 2011
	TR2/3/3A SU pistons sticking in TR3	Triumph	11	Jul 23, 2011
T	TR2/3/3A TR3 Sticking Brakes - How come and what to do?	Triumph	5	Jul 1, 2011
	sticking rear brakes	Austin Healey	8	Aug 18, 2010
R	sticking speedometer	Triumph	1	Jul 27, 2010
	TR4/4A Sticking Accelerator or SU Jets: TR4A	Triumph	7	Jul 9, 2010
	SU Choke sticking! Help	Triumph	6	Jul 6, 2010
	Jet Assembly sticking	Triumph	6	Jun 14, 2010
	AH 3000 Overdrive - sticking engaged	Austin Healey	4	Jun 6, 2010
R	1275 timing/ carb pistion sticking	Spridgets	3	Dec 29, 2009
K	Sticking Floats	Triumph	12	Nov 18, 2009
	Sticking back brake BJ8	Austin Healey	0	Sep 10, 2009
M	Bugeye clutch pedal sticking	Spridgets	2	Aug 29, 2009
R	TR2/3/3A TR3a- grose float valves sticking	Triumph	6	Jul 22, 2009
B	Sticking float valves	Spridgets	12	Apr 29, 2009
	1500 Midget; sticking choke	Spridgets	6	Sep 15, 2008
	Sticking horn push	Triumph	8	May 14, 2008
A	carburettor air valve sticking	Triumph	3	Apr 24, 2008
	Choke is sticking ???	Spridgets	11	Apr 23, 2008
	Gas pedal sticking - maybe the cable?	Spridgets	15	Dec 18, 2007
	Sticking Shock	Spridgets	2	Aug 3, 2007
D	Sticking Brakes	Spridgets	22	Jun 15, 2007
X	Throttle linkage sticking	Spridgets	6	May 9, 2007
B	Is my Thermostat Sticking?	MG	9	Apr 29, 2007
R	Clutch Sticking Problem	Austin Healey	4	Dec 30, 2006
	sticking butterfly	Spridgets	8	Sep 17, 2006
	Steering Rack sticking	Triumph	4	Jul 21, 2006
T	Sticking throttle - any ideas?	Triumph	8	Jun 20, 2006
T	Likely cause of throttle sticking open	Triumph	5	May 8, 2006
B	Carb Problem - Something's sticking	Austin Healey	43	Feb 11, 2006
	Transmission sticking in 1.st	Spridgets	3	Dec 12, 2005
D	Sticking Bonnet	Spridgets	4	Nov 20, 2005

TR6 Sticking TR6 throttle

Share this page

Senior Member

Yoda

Darth Vader

Senior Member

Yoda

Luke Skywalker

Senior Member

Jedi Warrior

Great Pumpkin

Senior Member

Yoda

Yoda

Senior Member

Yoda

Great Pumpkin

Yoda

Great Pumpkin - R.I.P

Great Pumpkin - R.I.P

Attachments

Senior Member

Yoda

Similar threads