YS Engine YSS7138 Regulator Spring for Use in Regulator Assemblies  [YSS7138]

Fitment and compatibility notes

The YS Engine YSS7138 regulator spring is supplied as a spare spring for regulator assemblies used with YS Engine equipment. It is intended for measured adjustments and for maintaining correct regulator function without replacing larger components.

By setting regulator preload, the spring influences throttle return and idle characteristics; hobbyists commonly change springs to make small, controlled adjustments to engine response. The part is sold as an individual spring element to be fitted into the regulator mechanism.

Fitting is performed inside the regulator assembly: remove the housing cover, take out the existing spring, and install the YSS7138 in the same orientation. Confirm idle and throttle travel on the bench prior to running the model to ensure correct operation in a controlled setting.

Sold singly as a low-cost service part, this spring is for model use only and not for any full-scale vehicle applications.