Old Kawa' 300 cutting out

[The-Machinist]

I hava an 86 kawasaki js300a ski that sat for 3 years. I have cleaned and put in a carb kit and a new plug, but it still cuts out at wot. It will run great wide open for about 30 seconds, then it(and me) falls on its face. It has very hot spark and compression of 155 psi. I have also replaced the fuel filter. Does anyone have any ideas as to why this is happening?
Thanks for any advice, Shawn.

 

[The-Machinist]

Re: Old Kawa' 300 cutting out

OK, update. I did some checking and when the previous owner removed the oil tank he just unhooked the oil line and let it lay. As it was it was laying in the bilge sucking up water and pumping it into the engine. so I removed all that stuff and capped off the fitting by the reeds that the oil/water flowed through. Now it will run a little better but still bogging out at wot. Is there any thing else that needs to be addressed concerning the oil pump unhooking? In theory it should run unhooked like this,,right? I am pre mixing the fuel at 50-1 is this correct?
This is my first pwc and as you can tell I dont know a whole lot about them. I picked it up for $20 so I dont mind putting a little money into it.
Thanks for any advice, Shawn