Strange Flooding Condition?

Obligatory picture for everyone’s viewing pleasure. This is the day we purchased her, June 2017. Apologies for the saga, but I have read enough threads on here to know to post a picture and provide all of the details in the original post to get quality replies!

2005 Ski Nautique 206 with ZR6 Engine. (yes the decals are not original but I’m a huge fan of the retro graphics of the 2006-09 model years) I do not know much about the history of this boat other than it began its life as a showboat at SeaWorld Orlando. I purchased with 415 hours on the engine and have added 40 to it in my first year with it.

In May of this year I was convinced that I was not getting full power out the engine, especially when pulling skiers out of the water. My confidence on engine diagnostic is not high (though I hope to improve that!) and for the sake of convenience I took it into Buxton Marine in Lewisville to have them give it a once over. They discovered that one of the cylinders was misfiring (completely unknown to me!) and thus my lack of power throughout the entire first year of ownership! Cause of misfire ended up being a bad fuel injector which they replaced and also refurbed the other seven. Took the boat back to lake and it drove like a brand new boat. Needless to say I was thrilled with the result until the boat sputtered and died. Took it back to Buxton and they found that the low pressure fuel pump was full of sand…so that was obviously replaced and really has me concerned about the boat’s history. Any other things to look out for if sand was found in the low pressure fuel pump?

So here is the mystery condition which has stumped the techs at Buxton and that I lay before you all, the wise and mighty CCF council: If I start the engine from cold, it will start normally. If the engine has been turned off and rests for more than 5 minutes, it will crank but not start until I open the throttle which makes me think some sort of flooding is occurring? But here is the kicker: if it rests for 30+ minutes, it will start normally without opening the throttle. The last thing that Buxton replaced was the throttle body control valve which they suspected was the culprit of a leak. But the issue continues even with the replaced control valve. Any ideas?

If it puffs grey/black smoke when you open the throttle to start it, you are correct it is flooding.
Flooding in a Fuel Injected engine would be the result of a leaking injector.
Easy to test for this. A test would be to connect a Fuel Pressure gauge with a long hose on it to this test port..   Drive the boat and watch what happens to your fuel pressure while driving and while it is reluctant to start.
Look up your specific pressure but I think it will be around 50 PSI. The number is important, some engines will run perfect with 47 PSI but the injector will not pulse at all with 43 PSI. Do some reading on your engine and know the numbers before trying to diagnose.
Note; Turning your key from off to on 2-3 times will pressurize the fuel system to Max Pressure.
The Fuel Pressure will bleed down when you are parked with the engine off but there is a bleed down number that tells you if you are in range or out of range.
The Bleed down number might say your system should hold pressure for 5 minutes and then lose no more than 5 PSI in the next 5 minutes.

You may find you have a fuel supply issue.   Next time it is acting up unscrew your fuel cap and see if there is vacuum.   If there is, your vent is plugged.
Could also be the tank filter or anti siphon valve not working properly.
Good Looking Boat, Get Err Running!

Jody,

The only sensors near the flame arrestor are the Idle Air Control valve and the Throttle Position Sensor. Do one of those have a temp sensor on board? Or do I need to replace one of those?