it seems only when towing skiers, and passengers aboard is when it is most likely to happen but that isnt always the case.
Those conditions involve higher fuel flow, higher RPM's, and more bumps/vibration than just sitting, idling, or being on the trailer. Those are clues - we just don't know to what, yet.
i pulled all plugs this past weekend and cleaned them but it didnt help. plugs were very dark and very wet.
Good. That means you're getting fuel. Try this: When it happens again, remove one plug, dry it completely, put it back in, crank again for 10-15 seconds, and then check the plug a second time. This will confirm you're getting fuel RIGHT THEN, and that it's not left over from the last time the engine ran.
engine compartment smelled like gas.
As noted by the other responder, that may indicate a fuel leak. However, the engine runs sometimes so obviously the fuel leak isn't preventing the engine from running. If your fuel lines are the originals they may have deteriorated and need replacing. Rule of thumb is replace fuel lines every five years. I just did mine (after nine years) and the slight fuel smell I had noticed occasionally has vanished. I had no evidence of a fuel leak but the fumes were obviously getting out somewhere. Worry about that after you solve this starting problem.
Also, the engine compartment will get smelly when you crank like this for a long time without starting because you're running raw, unburned fuel through the engine.
problem happens with kill switch connected and disconnected.
OK, that's one of at least four things I can think of that can short the CDI's to ground. The others are the keyswitch, RPM limiter, and throttle guardian. They all tie into a black-with-yellow-stripe wire that goes to the CDI modules. Any of these devices grounding that wire will stop the engine and prevent it from starting - but they will NOT prevent it from cranking.
First, please try the dried plug test above to confirm you are getting fresh fuel when the engine won't start.
Next, you're going to disconnect the CDI grounding circuit. I'm doing this from memory (engine is ~40 miles away) so bear with me.... As you look down at the top of the engine the cylinders are toward the rear of the engine. Above the right bank of cylinders, on the top of the engine, are two black plastic rectangles mounted one over the other. The top module is the RPM limiter. Find its wire bundle and trace along each wire; I believe one of them is already black-with-yellow (the CDI wire). The CDI wire crosses toward the center of the engine where it meets up with other such wires and connects together with them. From that junction, a single black-with-yellow goes back toward the cylinder heads, spark plugs, and CDI modules.
That last wire, the one going toward the plugs, is the one you want to disconnect. IIRC you may have to disconnect two connectors to isolate that wire, but they're all bullet connectors that just pull apart. Your goal is to electrically isolate that wire so nothing is connected to it. That way nothing in the boat can ground the CDI's. Keep track of what you disconnect so you can reconnect it later.
CAUTION: Once you do this the normal methods of protecting and stopping the engine won't work anymore. Stopping the engine will rely solely upon the keyswitch killing power to the ECU, which will in turn stop firing the injectors and the plugs. The engine may not stop instantly, so be prepared. Also, you will have no overrev protection so if you do this on the water do NOT go over waves that could bring your jet intake out of the water. Basically, just use your head.
Isolate that wire, then try starting. Report back!
