2004 Speedster 240 ERI Merc wont start in the water

[rattlesnake]

Hello all,
I purchased a 2004 Speedster with a 240 Merc 2 stroke. Had it on the water twice, tubing with the kids, ran great, no issues at all... 3rd time out, knee boarding a bit, boats running great, shut the engine down so my wife could soak a bit.. 15 minutes later, tried to start it and it would not start. Cranks fine, but does not attempt to light off. lifted the engine cover, let it sit for another 15 min, still wont start.
We got towed back to the ramp, loaded up the boat and went home. 15 mins later, in my driveway with hose hooked up the engine started on the first bump and ran great...
Im assuming the back pressure from the water has to be an issue, but im at a loss.
Any ideas would be greatly appreciated.

 

[Dr Honda]

welcome... and this should be in the Merc section. I'll move it for you.

I'm going to assume you have a gen2 240EFI engine... but please post a pic so we know what engine you have. (Big differences between Gen1 and Gen2)

 

[rattlesnake]

Thank you, new to forums.
Not sure if gen 1 or when 2.
I've attached a few pictures.

 

[Dr Honda]

OK... thanks. That's a Gen2.

It can be a few things. Since you had the deck lid up, and fresh air in... we will go past that. Also... since it restarted later... we known it's nothing major as far as mechanics.

One part that comes to mind, is the "Throttle Guardian". It was an add in box from Seadoo that is supposed to keep the RPM's low in neutral and reverse. But, they are known to fail, and cause random problems. Look in the helm... and see if there is a box with some wires coming out of it. (other than the fuse block) If there is... remove it.

The other thing it could be, is the lanyard post. The one in my boat went bad a couple years ago, and we've had a rash of them this year. Personally, I feel they are unneeded in the bigger boats, and I would just disconnect it. If you want to keep it... I would cut it loose (The Black Yellow wire) just for a test. When they go bad... the contacts go intermittent. When mine decided to go bad... my boat would start, and run fine... and it would just randomly shut down.


The last thing it could be is a flooding condition. This is normally caused by leaky injectors. That gets a little more involved, so lets look at the electrical first.

Oh... if you think about it... stop by an auto parts store, or Harbor Freight, and buy an in-line spark tester... and put it in the boat. If you are out, and this happens again... you can plug that on, and see if you are getting spark or not.

 

[rattlesnake]

Thanks Doc
I picked up an in line tester yesterday before I took the boat out. Played around for an hour.. went to the dock to test it and it started fine
Now, I read that if the battery voltage is low it will Not engage the fuel pump.. do you know if that is correct.
I really appreciate your input. I'm looking into the items you mentioned today. I guess I have to wait to see if it happens again.

 

[Dr Honda]

One some of these ECU's... they don't like low voltage. SO... you may have 12v... but when you go to crank... the voltage will sag. If it drops to 10.6v or so... it will continue to crank... but the ECU may not fire the injectors. A quick check with a volt meter will tell you the condition of the battery while cranking, better than any "Load Tester" at an auto parts store.

So... if you have a weak battery... then yes... just replace it to be safe.

 

[rattlesnake]

Tested it at the lake, on start, battery drops to 10.4V.

 

[rattlesnake]

Just an update... been running the boat each weekend at the lake and the problem has not shown itself again. I recall that I changed the water separator prior to the problem occurring.. I'm hoping that it was a minor issue brought on by that... doesn't make sense, but knock on wood, it hasn't reoccurred.