Marvin PH4 Pruner Spring

The Marvin PH4 pruner spring is the return spring that pulls the blade back open after each cut on a Marvin pole pruner. Once it weakens, the head hangs closed and every cut takes longer.

A small part that sets the pace

A pole pruner is only as fast as its spring. When the spring is fresh, you pull, cut, let off and the jaw is open for the next limb. When it is worn, you are shaking the pole and waiting. On a long day of clearance pruning, that adds up.

Replace the spring when it shows gaps between coils at rest, the hook end is worn thin, or the blade no longer opens fully on its own.

Springs fatigue faster when the head is stored wet, packed with sap or left with the blade pulled closed. Clean the head at the end of the day and hang it with the jaw open where you can. That spreads out replacement, but springs are still consumables. Buying a couple at once means the next one is waiting when the blade starts dragging. Keep a small parts box in the truck with the springs, bolts and links your heads use. A ten minute repair in the yard beats losing half a day of pole work to a part you could have had on hand.

Swap and inspect

Note how the old spring hooks in, remove it and fit the PH4 in the same position. Work the blade by hand to confirm a full, smooth return. While the head is open, look over the blade edge, pulley and pivot hardware.

Keep a spare spring with the pole kit if you run Marvin heads daily. For heads, adapters and poles, see our poles and pole kits section.