Anyone know anything about 2 stroke yamahas?

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dieselDaryl

dieselDaryl

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I bought a 99 WaveRunner 700XL (701cc) a few months ago and its been good until recently. When I'm turning really hard, as the turn gets tighter and the ski banks steeper, the engine lugs to about 1/3 and just stays at that power.. once I straighten it out and it tilts back upright up a few degrees, its instant full throttle again. Originally it only did it when I was turning left but now it does it left and right..

Any ideas? I was thinking carb float is sticky? I already checked the throttle linkage, and water seperator.

I know my way in and out around diesel cruisers but when it comes to 2 strokes I have NF clue. Any help is appreciated!

TIA,
 
beaufort-fj60 said:
2 stroke boat motors are problematic, (i'll probably get flamed on that one) take it to a yamaha dealer and let them tune it.
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Thats the current plan.. However they are super busy out here (Okanagan) so its a 2 week wait. I changed the spark plugs and its running better overall but my gut feeling is that the problem has to do with fuel starvation. The other thing I've noticed is that the fuel filter is only about 4/5 full. Its got air in the top of it, I don't know if thats right or if it has to be bled somehow..

Wish I could afford a newer four stroke..
Daryl
 
Thats why I got rid of all carb operated vehicles and now own only diesel cruisers :)

I was thinking of running carb cleaner or some sort of fuel treatment through it. The Yamaha guy initially said it sounded like something electronic..

Daryl
 
If you have an oil resevoir for oil injection, you may be causing it to read low enough to indicate low or no flow while you are in the steep/sharp turns.

My 200's have a primary oil tank in the bilge and a secondary on each engine. My secondary tank on one engine wasn't filling up properly which triggered a low oil alarm. The engine then goes into safe mode and won't rev high so as not to cause any significant damage yet still get you back home. It does this by altering the timing and firing order.

I would suspect your oil if you have oil injection and don't mix your gas and oil yourself.
 
Capt. Jim said:
If you have an oil resevoir for oil injection, you may be causing it to read low enough to indicate low or no flow while you are in the steep/sharp turns.

My 200's have a primary oil tank in the bilge and a secondary on each engine. My secondary tank on one engine wasn't filling up properly which triggered a low oil alarm. The engine then goes into safe mode and won't rev high so as not to cause any significant damage yet still get you back home. It does this by altering the timing and firing order.

I would suspect your oil if you have oil injection and don't mix your gas and oil yourself.
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Yes, it has oil injection. I just recently topped up the oil tank up but maybe the sensor is giving out at some point. I will check that out tonight if I can.. Thanks.
 
I don’t quite understand your question. Is it changing RPM’s or is it just not accelerating?
If it’s changing RPM’s I agree with what everyone else is saying, if it’s not, could it be getting too much air mixed with water? Preventing good thrust?
Just trying to help man, I live in the desert!
DMX
 
No, its dropping RPMs big time. It was working fine before but now this problem has creeped up. Basically I hold the steering tight to one side and the turn gets tigheter and tighter and the ski banks more steeply and then the engine slows down and i do really slow donuts until i straighten the steering and the RPM comes back up instantly. Its not a matter of lack of water going through the jet drive. the engine noticably bogs down..

Daryl
 
maybe try what Capt. Jim suggested in a round-about way. Pre mix your gas before putting it in the jet ski, that will at least give you and answer on if the oil injection is working or not. if it still bogs when premixed it's not the oil injection.
 
I agree with the pre-mix. It'll only be your own fault if you forget to mix your gas, not riding around waiting for the injection pump to fail. I had two fail on two different outboards (BTW, notorious failures on early Johnrudes) and I have plugged the oil line on every engine since. You might also try a decarbonizer, I forget Yamaha's brand, but OMC/Bombardier brand is called "engine tuner". Run the ski on the hose and spray it directly in the carb until it wants to choke out (it'll smoke...a LOT), use the whole can, shut it off and let it sit for a while. Crank it up and run it till it clears up. May not be the solution, but it has helped a few of my engines run a little smoother.
 
Conex said:
I agree with the pre-mix. It'll only be your own fault if you forget to mix your gas, not riding around waiting for the injection pump to fail. I had two fail on two different outboards (BTW, notorious failures on early Johnrudes) and I have plugged the oil line on every engine since. You might also try a decarbonizer, I forget Yamaha's brand, but OMC/Bombardier brand is called "engine tuner". Run the ski on the hose and spray it directly in the carb until it wants to choke out (it'll smoke...a LOT), use the whole can, shut it off and let it sit for a while. Crank it up and run it till it clears up. May not be the solution, but it has helped a few of my engines run a little smoother.
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Ring Free is the product you add to the fuel or you can run Chevron gas which has Techron in it, the same thing.
Check Capt. Jim's response, also change the fuel/water seperator and get a manual so you can do the timing and a link and cync on it.
 
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