Stiff Throttle on new TX

[NorthernProducer]

I just replaced my wife's CX with a new TX and she loves it except for the stiff throttle. I checked out the cable and carb linkage and they are free from any sticking or excessive tension. Seems the extension spring that hooks to the throttle pedal linkage is pretty stiff, and is the source of the problem. My dealer will only use the stock replacement spring (M160852) which does not fix the problem. I know JD used a different part number (M141788) for the older TX, but not sure it fits and will solve the problem. Has anybody solved this problem? Thanks.

[NorthernProducer]

Update: I found the old TX throttle spring had higher level of resistance, so that would make the situation worse. Eventually tried a universal throttle return spring kit available at most auto parts stores for carburetor equipped cars. These springs with main and backup springs. I used the smaller diameter spring and that solved the problem. Note this spring measures about 4.5 lbs/inch of return pressure. which is about 1/3 of the factory spring. The wife is happy now, so I consider this problem closed.