GTI LE won't run in the water

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2003 720 gti le won't run under load. New battery, carb, stator, recrifier in last 1.5 years. engine has about 45 hours on it since it was rebuilt. New ignition coil coming in tomorrow. If that doesn't work, what do I try next? Starting to feel like a dead end. It starts and idles, but then under load dies after a couple minutes. Won't start at all in water or for only a brief moment.
I'm no expert...but if it starts and idles then quits under load....that usually points to a fuel delivery problem to me. You stated "new carb"? When? The craft is 17 years old.....I'd re-build the carb(s) just as a matter of maintenance at this point.....use ONLY genuine MIKUNI carb parts.

Opps, didn't interpret your note carb in the last 1.5 years.....I'd still look into the carb.....I assume all old fuel lines and the selector switch have been replaced as well, pressure test the fuel system for potential leaks, too!
Carb was brand new from Mikuni last season and set to factory specs, never ran with it besides testing. Fuel lines are all new as well. Motor was installed in 2014 new/reconditioned (unsure which) from SBT but the guy who did it messed up the stator by not checking the magneto when he put it back together for foreign objects (razor blade). I didn't replace the lines coming from the tank yet, but I did from the filter to the carb, but I'm doubtful they are bad since there is nothing in the fuel filter. I haven't changed out selector switch...that honestly never was even a thought.
A factory carb out of the box may not run perfectly on a re-built engine...some fine tuning might be in order. I'd still be looking at the fuel delivery system.

My old '96 gave me fits, ran fine on the trailer, would not run under load (in the water)....finally came down to a thorough CARB re-build (both) and some tweeking/adjustments and fine tuning to get everything back into sync (fuel delivery, oil delivery) etc.....good lucj with it....they certainly are an exercise in patience.
Forgot to mention, when I got it, I was told it needed break in and was given wrong instructions I was told after the fact about adding extra oil in with gas on top of the machine pre mixing. Could this have caused a lasting issue I am not thinking of?
I would check the compression before going further. Don't use a Harbor Freight gauge.
Compression was checked last year and it was good (wasn't told numbers, had it done at a shop when I had starter done). Just went through the lines and they all look brand new inside and out (of course out... It's spotless). I did have a thought and rechecked gap on the plugs (including older spares and new set of spares, and new ones in motor) and every damn one was set wrong from the manufacturer. My mistake trusting NGK to do their job right so I reset all of those to proper gap. Once I get new ignition coil in, I'll see what it does and go from there, starting with carb tune.
You need to check the compression and get the actual numbers.
Also make sure your gas tank vent iis working.
Definitely will.
OK, so I'm really bored being in NY I re-read your notes and something you said jumped out at me now:
-> You have not replaced the fuel lines from the tank to the fuel filter...BUT you have from the filter to the think it's OK since the filter was clean. Uh oh....the BIG filter is easily reachable and easily replaced, so of course it would look clean.....the problem lies in very tiny particles getting PAST the fuel filter outside the carb(s) AND also even tinier particles getting past the INTERIOR fuel filter(s) inside the carb(s) themselves. You have NO IDEA how frustrating it is to THINK your carb(s) are good, until you tear them down and physically get in there and start cleaning/rebuilding doesn't take much to bugger up really tiny passages inside a carb to wreak havoc on your ski's performance......TRUST US, this is a very common issue.
Checked all the lines yesterday morning, everything was good. New carb has about 4 minutes of run time on it since I put it in. I have no idea where to start for tuning it though, just set it where Sea-Doo said it was supposed to be. Waiting for weather to cooperate so I can finish putting in new ignition coil since I can't fit it back in the barn with the snowmobile put away.
A stock seadoo will run perfectly with the stock settings. If it won't something is wrong.
Ended up hitting it with my purse. Final outcome was the new carb had the wrong jets, new starter wasnt new and the dude screwed me on it when it was put in, and the flywheel was messed up. Runs good now, after a large hit to the bank account and my ego for being unable to fix it my damn self lol.
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