Engine Rebuild

Overview
This project involved the full restoration of a 1997 Sea-Doo GTI, with the primary focus being a complete engine teardown, rebuild, and reinstallation. Secondary efforts included cosmetic upgrades to the hull.

Additional tasks not detailed here included rebuilding the jet drive, fuel system flushing, exhaust manifold repair, and light fiberglass and electronics repair.

Figure 9: Reinstallation (Carb, Exhaust, Raw Water Cooling System, Fuel, Spark Arrestor, etc.)

Figure 1: Sea-Doo GTI striped and cleaned

Figure 2: Graphics Mock-Up via Photoshop

Figure 3: Engine Removed

Figure 4: Workshop Disassembly — Ignition Coil

Figure 5: Workshop Disassembly —Top End

Figure 6: Workshop Disassembly — Bottom End

Figure 7: Workshop Disassembly — Crankcase

Figure 8: Crankshaft to be Replaced

Figure 10: Completed Rebuild
on the Annisquam River, MA

Cosmetic Improvements
The hull was stripped of its original decals, washed, buffed, and waxed. A new design was drafted in Photoshop to visualize changes, including custom-cut decals and a reupholstered seat to give the jet ski a new look.

Engine Removal
The old engine was removed and the oil-fouled engine bay was thoroughly cleaned. All hoses, fittings, and hardware were carefully labeled for reassembly.

Engine Rebuild
During disassembly, compression testing and bore measurements revealed the top end needed new rings, gaskets, connecting rod bearings, and pistons. While apart, the cylinder walls were honed, oil galleries flushed, and any salt deposits within the raw water circuit removed.

Engine Rebuild - Cont.
The lower end inspection showed severe bearing wear on the crankshaft, with loose metal fragments present, making replacement necessary. A rebuilt crankshaft was sourced and installed along with new seals and bearings.

Reinstallation and Alignment
After reassembly with proper torque specs, thread locker, and lubrication, the engine was ready to go back in. Positioning was critical to ensure proper alignment between the crankshaft and drivetrain. Shims were used beneath the engine mounts, and a dial gauge confirmed coupling alignment by measuring shaft runout. Once secured, new fuel lines, exhaust connections, and a temporary raw water supply were installed making the engine now ready for initial startup

Outcome
After priming and a few cranks, the engine roared back to life. Needless to say, it was a very rewarding project and restoration. This project was motivated by the shutdowns surrounding Covid-19 and ended up being a very fulfilling way to make the most of quarantine.