The Symptoms:  The port-side engine on this jet-boat has simply stopped running. Listening to the sound when attempting to crank the engine suggests an internal engine problem.

The Problem:   A compression test confirms a serious problem with at least one of the engine's cylinders.

The Fix:

The Symptoms:  Rapid bearing wear - Stuffing boxes wear out and leak - Bent or broken shafts - Drive system vibration that can damage transmissions, engine mounts and the boat hull itself 

The Problem:  Incorrect alignment and poor or worn out engine mounts.

The Fix:  Replace/Upgrade struts, strut bearing, engine mounts. Sometimes flexible rubber engine mounts are installed on engines to reduce the amount of vibration transmitted to the hull. Where an engine has flexible mounts and rigid gearbox and shaft couplings, the mounts move but the shaft doesn't. A gyrating engine results in a misaligned propeller shaft. This causes shaft vibration and wear of the gearbox bearing. On drive trains equipped with a dripless shaft seal, the increased movement can cause the seal to leak. The only remedy is to modify the shaft by installing a flexible coupling.

The Symptoms:  Very rough idle and stalling of the engine at idle speed.

The Problem:  If the problem started all at once a good first place to start would be contaminated fuel.

The Fix:  Never buy gas at a service station when the tanker truck is filling up their tanks or shortly thereafter! They count on water present in the storage tanks to remain on the bottom below the outlet going to customer pumps. Since gas is lighter than water this works quite well. But after dumping five or ten thousand gallons of new gas in, it does a bit of mixing, in a short while the gas and water separate again and all is okay . If the boat is not already equipped with a fuel-water separator between tank and engine, install one.fue

The Symptoms:  Engine won't turn over.

The Problem:  Neutral safety switch bad - Breakers and batttery switch set incorrectly - Battery voltage okay ?

The Fix:  Inspect battery terminals; clean and tighten. - Check all big wire connections, especially ground connection. - Check large fuse in starting ciruit. - Label, remove, clean and re-attach wires on starter solenoid. - Check voltages at starter solenoid: - Large red wire should have battery voltage, - Trip-wire S terminal (connected to ignition) should have zero or battery voltage depending on ignition switch position. - Turn battery switch off and tap sides of solenoid and side and end of starter motor lightly with hammer. Then try to crank engine. - Turn battery switch on, and repeat tapping while someone else turns ignition key on and off rapidly. Then try to crank engine.