• Hey there Guest!
    If you enjoy BCF and find our forum a useful resource, if you appreciate not having ads pop up all over the place and you want to ensure we can stay online - Please consider supporting with an "optional" low-cost annual subscription.
    **Upgrade Now**
    (PS: Subscribers don't see this UGLY banner)
Tips
Tips

TR4/4A idle

Rut

Obi Wan
Country flag
Offline
idle is too high, 1800 and won't come down.
Look for a manifold or carb leak and also check your linkage. Sometimes the shaft that connects the gas pedal to the carb linkage can bind. Do you know the person from Spanish Fort who sold the 69 TR6 on BAT?
Rut
 

lram59

Member
Country flag
Offline
On my '63 with H6 carbs it was worn shafts and butterflies or discs or whatever you want to call them. If you take a the carbs off and shine a light from the back with the pistons lifted you should see very little light shining through. New shafts and discs and the Joe Curto videos and my idle is 700 rpm.
Larry
 

bobhustead

Senior Member
Gold
Country flag
Offline
If the car is so equipped, have you checked the idle screws on the carbs & the fast idle cam, as well as the fast idle cam itself for free movement?
Bob
 

Stevenry

Senior Member
Country flag
Offline
+1 on the discs. I ran out of adjustment on the rear carb, and after centering the disc I have screw left over and I think it idles at about 950. My tach isn’t totally accurate, but I have had a dwell/rpm meter on it during tuneups. I don‘t doubt my shafts might be a bit worn, and I have a bit of a cam.

But kind of on the topic, I can get it to idle a bit slower, and it will maintain that idle all day, probably, just tooling around, but I find that at the end of an off ramp after 10 minutes at 70+, (distance to golf course) it idles so slow it’s about to stall. Once I get moving again, it’s back to it’s normal idle. Does anyone else experience this, and perhaps know the cause? Has it gotten too rich decelerating to the stop?

Steve
 

Sarastro

Obi Wan
Silver
Country flag
Offline
It would be helpful to know a little more. I assume you have tried adjusting the idle speed, but you can't get it down to a sensible level, yes? If so, I would make sure that the throttle is not hanging up on something. Then loosen the throttle connections between the carbs, disconnect the linkage to the accelerator, and again try backing off on the idle. Be sure that the throttle levers are actually moving when you do that; sometimes, the springs get weak or they develop friction or won't move past some point because of gunk buildup. Of course, make sure that the choke cam is not holding them open.

If you still can't get the idle speed down, almost certainly you have an air leak in the carbs or a throttle plate that isn't closing. The carb bodies are made of a zinc alloy, which wears easily around the throttle shafts. The throttle plates can even wear into the bores of the carbs.

You can put bushings into the carbs to fix the shaft wear, and install new shafts, but it requires machining the carb body and you may not be up for that.
 

sp53

Yoda
Country flag
Offline
Perhaps the jet is not returning after the engine has been choked. See if you can push the jet up until it rest at the base of the assembly, they sometimes can stop about 1/8 of an inch before returning and cause a fast idle. I look at the spark plugs a lot when I am trying figure stuff out in that area. Idling at 700 rpm on these cars requires everything to be just right; at least that is my experience.

A lot of Steve’s on this post, my car will idle slower and almost die after a drive at 60 or 70. What I found out was the engine has cooled down about 5 to 10 degrees from all the cold air and is dying because of the engine temp. The engine then warms up that little bit in slower traffic and runs as normal as tr3. So, sometimes I will pull the choke out a little for a moment after a long drive in the mountains when coming to a stop.

steve
 

poolboy

Yoda
Country flag
Offline
The mixture might be a little lean..assuming the ignition timing is suitable.
 

TR-3rg

Jedi Hopeful
Country flag
Offline
Hi,

Have you checked the mechanical advance in the distributer? Pop of the cap and twist the rotor. It should spring back to were it was. Try both directions. If not, its likely the return springs are broken and its stuck in full advance. If that's the case, its time for a distributor rebuild or replacement

Roy G
 

Zadymek

Freshman Member
Country flag
Offline
+1 on the discs. I ran out of adjustment on the rear carb, and after centering the disc I have screw left over and I think it idles at about 950. My tach isn’t totally accurate, but I have had a dwell/rpm meter on it during tuneups. I don‘t doubt my shafts might be a bit worn, and I have a bit of a cam.

But kind of on the topic, I can get it to idle a bit slower, and it will maintain that idle all day, probably, just tooling around, but I find that at the end of an off ramp after 10 minutes at 70+, (distance to golf course) it idles so slow it’s about to stall. Once I get moving again, it’s back to it’s normal idle. Does anyone else experience this, and perhaps know the cause? Has it gotten too rich decelerating to the stop?

Steve
I had that issue, check if air is not seeping in between carbs & manifold. I forgot what i sprayed around (starting fluid, b.cleaner or smthg that burns) If ur rpms go up - u have a leak, Just make sure u r not spraying from far & get it sucked thru intake.
changed both separating blocks & gaskets. It fixed that problem
 
Similar threads
Thread starter Title Forum Replies Date
D TR6 Gp 2 cam, head shaved ,shorter pushrods, with a rough idle Triumph 10
drooartz T-Series Can't get idle below 2000 MG 8
Tim Tucker TR4/4A Stromberg 175CD (c.1825) rich above idle Triumph 12
J MGB Idle problem MG 4
G HD8 Idle Adjust Screw Austin Healey 10
B Vacuum at Idle Austin Healey 9
D Lumpy Idle When Hot Austin Healey 2
E MGB MG Idle issues, restart issues solved. MG 4
K TR2/3/3A Oil pressure at Hot idle? Triumph 3
crispy Idle Speed Variation Austin Healey 19
K TR2/3/3A Slight surging at Idle? Triumph 11
skystryd remind me it's fun. good idle. rough when accelerating Spridgets 6
S TR2/3/3A I have this miss where the car will start and kinda idle Triumph 23
F TR6 Idle change when brake is pressed Triumph 4
P Carb Help - Car idle slows and dies after being run for a while Austin Healey 14
RAC68 Loose Metal Knocking/Banging Sound during Rough Idle Austin Healey 32
HighAltitudeTR3 TR2/3/3A Mini Pulses at Idle Triumph 6
SherpaPilot TR6 Strombergs with poor idle Triumph 11
C Rough Idle - What to check? Austin Healey 12
Tim Tucker TR4/4A Rich Idle Triumph 14
HalLucy Post-War Other Renown - Idle too fast Triumph 5
S Can’t get idle speed below 1300 RPM Austin Healey 28
edkap2002 TR6 Issue of the day......restart and idle after shut down Triumph 21
NutmegCT T-Series MG TD idle speed? MG 12
S TR2/3/3A Too much fast idle, not enough choke? Triumph 0
F TR2/3/3A Idle Triumph 10
S TR2/3/3A Carb Idle Question Triumph 6
S Some observations/results to slowly diagnose why my Healey overheats at idle Austin Healey 40
Lutz Kramer Pushing the clutch lets idle speed drop until the engine stalls Austin Healey 18
K TR4/4A Strombergs...wont idle unless choke pulled out? Triumph 7
wkilleffer MGB Air leaks and fast idle speed MG 11
Marla TR4/4A Idle spring? Triumph 7
D 69 E Type High Idle Jaguar 9
K TR2/3/3A Mild street cam and Idle? Triumph 13
Geo Hahn TR4/4A Stumble off Idle with Hot Engine on Hot Days Triumph 4
2billydavies TR2/3/3A very high idle, timing perfect Triumph 7
steveg Checking Healey Mechanical Tach at idle Austin Healey 3
steveg HD8s - getting below 1000 rpm idle Austin Healey 4
RAC68 BJ8: 650 RPM steady Idle at 45 Degree advance??? Austin Healey 26
J MGB Project car done: idle variable MG 2
J SU HD6 - Slow Idle Screw Austin Healey 13
K TR2/3/3A Refresh...main reson why idle will lower when kicking the gas pedal? Triumph 3
RickB MGB Stromberg on my 80 MGB - fast idle this morning MG 6
S Idle falls until car stalls Austin Healey 10
steveg HD8 high idle aggravation Austin Healey 11
S Ignition timing - I can't get less than 12 deg at idle Austin Healey 7
Geo Hahn TR4/4A Stumble Off Idle When Hot Triumph 4
Geo Hahn TR4/4A Stumble Coming Off idle Triumph 9
B Fast Idle Spridgets 7
AUSMHLY Idle does not stay constant, why? Austin Healey 22

Similar threads

Top