M2 210 Merc. wont start, Rebuilt last season, ran fine last week, something electric?

[alpine69]

Hi everyone

I have a 2001 Seadoo Challenger 1800 M2 210 tri-carb that was rebuilt last season as it threw a piston pin. Boat ran great at the beginning of this season, worked last week in water, although after resting in the water for a while it wouldnt start, and for almost an hour and after pulling the plugs and screwing around it finally did run fine.

Took it on a trip this week and it ran great for two days, brought it home and it wouldnt start when I put it back in the water, even after replacing the plugs with new ones. I took it to the marina that rebuilt the engine and it started 10 times in a row for them on the trailer, they couldnt find anything wrong with it. I towed it home and it started fine in the driveway, put it back in the water and it wouldnt start again. Now its back in my driveway and it wont even start on the trailer now..

I've:
-replaced the sparkplugs with new ones ($110 bucks yikes)
-checked that the fuel primer is working
-checked that the fuel pump is pumping
-checked the fuses on the engine
-battery is fine
-kill switch seems fine
-checked that all the connectors on the wiring harness on the engine are ok

It seems that it must be an electrical issue but I have no clue what could be causing this. ANY SUGESTIONS OF WHAT TO CHECK NEXT WOULD BE GREATLY APPRECIATED!!! thanks in advance

It's finally 110degrees out here in Canada, and I really want my boat back haha...

 

[alpine69]

Now its seems the (new) spark plugs are milky like there is water getting into the fuel system after its turned over a few times when hooked up to a hose in the driveway. I've drained the carbs and they seem clear unmilky mixed gas as expected. Where could the water be getting in?

 

[WAJetboating]

I towed it home and it started fine in the driveway, put it back in the water and it wouldnt start again. Now its back in my driveway and it wont even start on the trailer now

My experience is that when a jetdrive "runs fine on the trailer" but "doesn't run in the water" it's almost always a fuel delivery problem. A boat on the trailer requires almost no fuel flow to run the engine - there's no load on the impeller, hence no load on the engine. But drop it in the water and suddenly you need way more fuel just to start and maintain idle, let alone rev up the engine. Remember, the impeller is turning whenever the engine is turning... even if you're sitting still at the dock, it's trying to pump water.

Your later comment, about milky plugs, seems to confirm something isn't right in the fuel department.

One thought: You've checked fuel pumps and such - but as this is a two-stroke engine, it also gets oil in the cylinders. Have you checked the OIL system? Water there could have the same effect as water in the fuel. Just a thought.