Boat engine pullcord spool

thingiverse

This is a custom replacement spool designed specifically for the rope starter on an old Johnson outboard motor, typically found on models with a horsepower rating of 6 to 8 HP. Due to the manufacturer's decision to discontinue production, original parts have become increasingly difficult to locate, making this handmade alternative a valuable resource. To ensure the part's durability and accuracy, I meticulously recreated it using precise measurements based on the original dimensions. Additionally, I created an identical copy with thicker walls, which I believe are essential for a 3D printed part that can withstand regular use. By printing the spool horizontally, I was able to align the layers in the most effective orientation against shear stresses, reducing the risk of damage or breakage. For this prototype, I used PETG filament as a minimum requirement until a nylon print is possible, given my concern that PLA might be too brittle for reliable performance. So far, the results have been satisfactory, and I hope this custom spool will be helpful to others who may be facing similar challenges in finding replacement parts for their vintage Johnson outboard motors.