Only 1 Sparkplug Burned Up?

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So I installed the fuel line I was missing with the jet, I found that some other small lines were cracked, and I replaced all of them. I then ran the engine and it sounded better, but when I pulled one spark plug cap while it's running it sounded the same, and if I pulled the other spark plug cap while it was running the engine died. So basically... I'm still running on just 1 cylinder. Would you suggest me paying someone hundreds upon hundreds of dollars to rebuild my carbs, buying new carbs off of eBay, or daring to rebuild them myself (with my limited experience)? Also, I am going to double check that I am getting a good spark in my bad cylinder, last time I checked I had spark.
 
IF you follow my carb thread you should be fine.
Have you tried cutting the plug wires back 1/4" and making sure the caps are on tight?
 
So I installed the fuel line I was missing with the jet, I found that some other small lines were cracked, and I replaced all of them. I then ran the engine and it sounded better, but when I pulled one spark plug cap while it's running it sounded the same, and if I pulled the other spark plug cap while it was running the engine died. So basically... I'm still running on just 1 cylinder. Would you suggest me paying someone hundreds upon hundreds of dollars to rebuild my carbs, buying new carbs off of eBay, or daring to rebuild them myself (with my limited experience)? Also, I am going to double check that I am getting a good spark in my bad cylinder, last time I checked I had spark.
Mikidymac said both plugs fire at the same time which is true for most two cylinder two stroke engines, why don't you switch the plugs and the wires around and see if it runs on the other cylinder or if it still does the same thing. That would eliminate that problem/issue immediately and then you can move forward.
 
Mikidymac said both plugs fire at the same time which is true for most two cylinder two stroke engines, why don't you switch the plugs and the wires around and see if it runs on the other cylinder or if it still does the same thing. That would eliminate that problem/issue immediately and then you can move forward.
Except for the seadoo RFI and I think the DI, they idle on 1 cylinder for some strange reason.
 
The second cylinder does run when i squirt starter fluid in it, so the problem is 100% fuel supply to the PTO carb. While reading through the carb rebuild thread, I saw that I was supposed to use 5/16 in fuel lines for the supply lines. I used 1/4 in lines. Maybe that wasn't allowing enough fuel to get through so it is starving the rear carb. I am going to replace those today with the right lines and see if it makes any difference. And if that doesn't do the trick, either I need to rebuild my carbs (again) or hire someone to fix it all and do a complete tuneup.
 
I finally rebuilt my carbs!!! I installed them along with new fuel lines and tried to start it up. At first she turned over and then died off. This happened a few times, then it started making a loud cracking noise and my battery started to die. I gave up that day, and went back to working on it last night. I removed the spark plugs and they had a bunch of gunk on them. I tried starting it without the plugs to see what the problem was and everything sounded good. I cleaned the plugs and put them back in and the loud cracking sound happened again. Without the plugs in, the engine sounds normal, with them in, the engine makes a terrible loud cracking/clicking noise. I have no clue and fear the worst. My guess is either blown headgasket, starter motor (but if it sounds good without the plugs in, probably not), or maybe the pistons are shot. Does anyone know what this might be? Thanks.
 
I'm going to borrow a compression tester from a friend tomorrow and check. Thanks.

Here is a picture of what my spark plugs looked like when i pulled them out. one of them was a little black last time I ran it, but now it has more build up and dust and crap on it. The other was clean when last used.
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I believe its this. This is what was told told i NEED to use because seadoos are picky about it. This is just a picture i got online, but i think its the same stuff.
 
Well, I would never trust any oil that says for all 2-stroke watercraft and didn't specifically API-TC rated especially in a 951.
 
Ok. What exactly should I get? And where do I get it? Also, do you think I blew a headgasket? Sorry to ask so much. Thank you so much for all the help.
 
I just buy the Seadoo XPS full synthetic but now it’s called E-Tec full synthetic. $36 a gallon at Pro Caliber.

The amsoil Interceptor is good too.

If you blew a head gasket I would expect the plugs to be clean from steam cleaning.

When an engine is running lean it is hot and leaves the dry black carbon soot on your one plug. I’m not sure what that rusty brown deposit is.
 
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Ok. Thank you. I’ll check compression soon, hopefully everything’s all good. If not, at least I know what my issue is.
 
So the other day I checked compression and I was looking at 100psi and 110 psi. Although when instead of cranking, you have cracking, who knows if it can even get a good compression reading. I guess there is potential for this just being ground out gears on the starter motor, but I suspect it's worse. I think I've officially given up on this project. But I did learn a lot of really valuable stuff. I got a greater appreciation for the machines, I learned to spend the time and money to get the best parts and do it the right way the first time (I rebuilt both my jet pump and my carbs twice), I learned to plan in advance EVERYTHING you need to and should do before you try to run it, and I also learned if it isn't fully fixed, don't run it! For a 17 year old with little mechanical experience, this was a great journey that taught me so many good life lessons. Thanks everyone for your help. Hopefully someone can learn something from this. My last question is do you think i should try to sell everything together (remember its the internals and bottom hull of a 98 gtx ltd fiberglassed into a 14 ft skiff) or should I try to part out for more money? (trailer is probably worth $300+, I have rebuilt carbs and a rebuilt jet pump, and the boat is worth maybe 200$ with the jet ski hull protruding out the bottom of it and is registered w/ title)
 
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