RAC68
Darth Vader
Offline
Hi All,
An occasional stuck throttle is not uncommon. Given the "Rube Goldberg" linkage from the accelerator peddle to the carburetors with it's incorporation of the overdrive control linkage, it is somewhat amazing that a sticking accelerator is not more prevalent then it is. Add to the complexity of the linkage is the return spring setup. A lever clamped to the end of each carburetor shaft secures the spring on one end with the other hooked to a bracket on the intake manifold. Since the rotating lever is meant to maintain a constant spring distance to produce an even force through the full rotational travel of the carb shaft, any miss-adjustment or the lever or age-developed weakening of the throttle springs, could result in the throttle plates not closing. As a result and in short, occasionally the RPMs do not diminish as they should when releasing the accelerator peddle.
Will replacing with a stronger springs help?
After rebuilding my carburetors and remounting them on the engine, I found that my carbs would not shut down as previously expected and sometimes RPMs would even increase. To address the issue, I temporarily replaced my original throttle springs with stronger units. Although the throttle plates now closed completely and consistently, the added resistance increased initiating peddle pressure and, after passing the initiating point, the added foot pressure would cause the throttle to jump forward. Some may have found a good way of dealing with this issue but I went back to the original springs and now have ordered new versions.
I noticed that some Jaguars and TRs use a coiled shaft return spring set around the accelerator shaft and located right on the carburetor. This could be a better approach then the Healey setup and one that is less mechanically involved. This approach may provide a less complex approach that I may consider if the newly ordered springs do not resolve the issue.
Just my thoughts,
Ray(64BJ8P1)
An occasional stuck throttle is not uncommon. Given the "Rube Goldberg" linkage from the accelerator peddle to the carburetors with it's incorporation of the overdrive control linkage, it is somewhat amazing that a sticking accelerator is not more prevalent then it is. Add to the complexity of the linkage is the return spring setup. A lever clamped to the end of each carburetor shaft secures the spring on one end with the other hooked to a bracket on the intake manifold. Since the rotating lever is meant to maintain a constant spring distance to produce an even force through the full rotational travel of the carb shaft, any miss-adjustment or the lever or age-developed weakening of the throttle springs, could result in the throttle plates not closing. As a result and in short, occasionally the RPMs do not diminish as they should when releasing the accelerator peddle.
Will replacing with a stronger springs help?
After rebuilding my carburetors and remounting them on the engine, I found that my carbs would not shut down as previously expected and sometimes RPMs would even increase. To address the issue, I temporarily replaced my original throttle springs with stronger units. Although the throttle plates now closed completely and consistently, the added resistance increased initiating peddle pressure and, after passing the initiating point, the added foot pressure would cause the throttle to jump forward. Some may have found a good way of dealing with this issue but I went back to the original springs and now have ordered new versions.
I noticed that some Jaguars and TRs use a coiled shaft return spring set around the accelerator shaft and located right on the carburetor. This could be a better approach then the Healey setup and one that is less mechanically involved. This approach may provide a less complex approach that I may consider if the newly ordered springs do not resolve the issue.
Just my thoughts,
Ray(64BJ8P1)
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