A stiff shifter is usually a cable problem, not a transmission problem. Don't replace the transmission until you've exhausted the cable.
What to Check
1
Shift cable corrosion
33C-style cables seize internally from salt water intrusion. Disconnect at the engine and check cable feel by hand.
2
Adjustment
Cables stretch. Most controls need an annual adjustment of the shift detent.
3
Linkage seized at the engine
Rust on the engine-side shift bracket binds the lever. Lubricate and free with PB Blaster.
4
Transmission internals (last resort)
Only after cable and linkage check out — internal clutch wear or low ATF can cause hard shifts.
When to Call Us
Cable replacement is a 1–2 hour slip-side job. We carry 6–20 ft 33C cables and Mercury / Yamaha control kits.