96 GTX wont sustain full revs, sotty plugs

[Paul 1996]

I was out on the weekend, the previos owner of my ski was running two stroke outboard oil, because the guy that rebuilt the engine told him to. I ran the engine to drain this fuel then added a 40:1 mix of 91 octane and Seadoo XP-S oil. I put brand new plugs in it ( NGK BPE8? ), and now it pulls 7000rpm initially then the peak revs drop to about 5500 rpm, @ 40mph. Ive had the ski running consistently @ 55mph before on the old oil.
Heres the catch, When I back off the throttle and do a turn for a run in the other direction, the ski will get to full revs again, then back of to 5500. The info centre tells me the charging system is not working. Is this a low voltage situation, Coil cant keep up at high revs?
I gave the ski a run on the new fuel with the old plugs initially; NGK 7's which I have found out arn't the plugs for the ski, and the plugs had a dry mid grey deposit on them.

Any help would ge greatly appreciated,

 

[timmyboy76]

hey paul, think you need to go thru the carb/s. Also, if your premixing, make surethe oil your adding is labeled on the bottle "premix", if its injection oil, it wont mix the same..

 

[Paul 1996]

thanks,

It just strange that the dropping of revs only happened after I changed to the new oil mix, which is the yellow seadoo bottle.

Ill go through the carbs, as they dont look as if they have been touched in a while

 

[kustomkarl]

The color of the bottle means nothing. My seadoo 10w40 / 4 stroke oil, is in a yellow seadoo bottle. Read the bottle carefully.

Here is the recommended use of oil and fuel from seadoo. Your model should use synthetic or synthetic blend.
Use High quality low ASH API TC Injector oil.
Do Not use NMMA TC-W, TC-W2 or TC-W3 outboard motor oils or other ash less type 2 cycle oil. Avoid mixing different brands of API TC oil as resulting chemical reaction will cause severe engine damage. Never mix Mineral or synthetics oil together.

Never use fuel containing more than 10 % alcohol,( Methanol or Ethanol) as severe damage will occur. The minimum of 87 octane is recommended for most engines.
Karl

 

[Paul 1996]

THe bottle said for direct injection and carb engines, but mentions nothing about premix. The Seadoo dealer in town was the one who recommended it to me, and advised on the 40:1 mix ratio.