The opportunity and the trap

A repower is the biggest ticket a mobile mechanic writes — and the easiest place to lose money or reputation. The engine price is the visible number; the job is everything around it. Quote the whole job or don't quote it.

Before any numbers: the assessments

1. Transom — non-negotiable structural check (see the transom rot article). No pass, no hang.
2. Weight and rating: compare the new engine's weight and horsepower against the boat's capacity plate. A modern four-stroke can be substantially heavier than the old two-stroke it replaces — check the plate, and the scuppers/freeboard implications on older hulls.
3. What carries over and what doesn't — this is where quotes go wrong. Line-item every one:

• Controls and cables (old mechanical controls rarely match new engines; digital throttle/shift means new everything)
• Gauges/instruments (new engines usually want their own network displays)
• Wiring harness, battery cables (gauge and length per new engine's manual), possibly bigger battery per the manufacturer's minimum spec
• Fuel system: hose condition and diameter, primer, water separator, anti-siphon valve, tank pickup — many new EFI engines are intolerant of old fuel systems
• Steering compatibility and prop (the old prop almost never carries over correctly)
• Transom bolt pattern and mounting height — measure, don't assume

1. Disposal/value of the old engine — core value, sale, or disposal cost; put it in writing either way.

Structuring the quote

• Engine + rigging parts (itemized) + labor + sea trial and prop tuning + haul/launch or lift time if needed
• A contingency line for discovered issues, with the trigger conditions stated ("if fuel hose fails inspection...")
• Explicitly list exclusions: transom repair, tank replacement, gauge upgrades declined by customer
• Warranty registration and the first service interval booked into the price — it locks in the relationship

Common mistakes

• Quoting from the engine price list without seeing the boat
• "Reusing" 20-year-old cables and rigging to win the bid — the comeback costs more than the discount
• Skipping the water test and prop verification line — an unpropped repower isn't finished
• Not getting a deposit that covers the special-order engine

When to walk away

Rotten transom, a hull worth less than the engine, or a customer shopping three quotes purely on price with a boat full of red flags — pass politely. The repowers worth doing are the ones you'd put your name on at the ramp.