</font><font color="blue" class="small">( the spring looks ok to me!
It doesn't do it all the time either.
Bob )</font>
Lube the "B" plate good and keep your RPMs up (don't load the engine below 2000 RPM). If that doesn't solve the problem, add a bigger return spring.
In a nutshell...When the engine starts to lug down, the charge pump for the hydrostatic cannot pump enough fluid with enough pressure to bring the swashplate back to neutral. By keeping the RPM up or adding a larger spring, you help eliminate the problem. I still forget to keep my RPM up sometimes, and find myself reaching over to force neutral by pressing on the reverse pedal. I would say its a design fault of our NHs, but one I can live with.