Throttle sensitivity

[Parviz Ghahramani]

Hi,
I have a PA-30, the throttle for power increase behaves fairly normal. But, on reducing power from full throttle (on take off) I almost have to pull back more than 3/4 (of the full range) before I see any change in manifold pressure and there after a very small change makes a huge drop in manifold pressure. This makes it tricky specially when I am on the approach and landing where a very very small adjustment throws my power off (either too high or too low) due this over sensitivity of throttle in the low region. The linkage between throttle and engine is a series of rod connectors, and there seems to be no adjustment, any one can provide any idea if you have seen this problem and what is the best course of action to try, investigate or do about this issue?

Appreciate any ideas you can provide.

Parviz

[Kristin Winter]

Normally there is adjustment at the cable ends and it may be possible to adjust where the arm on the fuel servo sits which can affect the geometry of the throttle movement.

[William Hughes]

You may also wish to check the lines to your manifold pressure gauges as well as the gauges themselves...

[Phillip Larson]

[Phillip Larson]

On the ground...doing a run up, do you find the same delays you described in engine RPM? In other words....is it really a linkage problem? Throttle acting different is cause to be concerned. If it's always been like that, less so...but it isn't normal, so I'd have it fixed.

Also I just realized I gave you advice in the previous post that really should be accomplished by an A&P.