[Mgs] Cruise control!!!

Max Heim mvheim at sonic.net
Sun Apr 13 17:51:47 MDT 2014


Last year I was having a similar issue, except it was around 2500rpm, and
with HS4s. When I got around to tearing into the carbs, there were several
factors:

1. The piston on the rear carb tended to stick and not bottom out. Cured by
swapping in a new cap & piston set from a firend's pile o' parts.

2. The throttle spindle was loose in the clamp, which was severely worn. It
took some peening and filing to get an acceptable fit.

3. The throttle shaft was slightly flared out near the ends of the blade, as
if the blade had been force-fit slightly off center. The flared segments
would jam if the shaft moved fore-and-aft. I filed down the shaft.

Each "fix" improved it, but the problem didn't go away entirely until I had
fixed all three.



on 4/13/14 1:17 PM, Peter Chast at pchastnow at gmail.com wrote:

> Stuck Throttle plate - generally linkage related, could be choke.
> Stuck damper piston in bore. - either bent damper/oil level or foreign
> objects.
> 
> 
> 
> On Sun, 13 Apr 2014 16:13:54 -0400, gordies garage <mg_garage at comcast.net>
> wrote:
> 
>> Mostly familiar with HS4, but do you have a choke cam that could be
>> stuck?
>> 
>> Gordie
>> 
>> --------------------------------------------------
>> From: "Monte Jane Morris" <montejane at gmail.com>
>> Sent: Saturday, April 12, 2014 10:05 PM
>> To: "MG list" <mgs at autox.team.net>
>> Subject: [Mgs] Cruise control!!!
>> 
>>> Damnedest thing happened to me yesterday. 20 miles into a drive, I
>>> noticed
>>> that I wasn't decelerating when letting off the accelerator going down
>>> hills. I was "idling" at 3000 rpm (60 mph) like I had cruise control.
>>> Coming into a town, I had to use neutral, the handbrake, and turn the
>>> ignition switch on and off to get into a parking lot. Checked the
>>> throttle
>>> cable and it seemed OK; a small amount of play and still cinched OK (the
>>> cinch cable nut had NOT slipped) at the carb end and the accelerator
>>> pedal
>>> on the other. The throttle spindle was rotated to where it should be at
>>> idle, but still idling at 3000 rpm.
>>> 
>>> I drove it back home 30 miles (the last 5 on gravel with many 90 degree
>>> turns, yipps!) with creative use of the ignition, neutral, and handbrake
>>> once again. Coasted into the garage bay.
>>> 
>>> This is the first time this has ever happened to me in 3 MGBs over many
>>> years of driving. I'm sure the main cause was that I was bragging to a
>>> friend ONLY THE DAY BEFORE,  that it had become a very dependable car
>>> after
>>> getting rid of the electronic ignition many years ago:).
>>> 
>>> Suggestions as to where I start to look?

> 

--

Max Heim
'66 MGB GHN3L76149
If you're near Menlo Park, CA,
it's the primer red one with chrome wires


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