2004 Yamaha XLT 1200 staying on plane

[brownjjst]

I have been trying to figure out why my ski will take right off up to about 20 mph then boggs down as if it sucked something up and losses power? I have changed the fuel in it, took apart the fuel lines as well as the filter inside the tank, and changed plugs. Seems as if it’s sucking air from somewhere! Any help would be greatly appreciated!!

 

[Scottintexas]

do your rpm's decrease or you have full rpm and just loose torque/speed ? how do your impellers look?

 

[brownjjst]

RPMs decrease and I have no torque. I have a good power coming out of the hole but when he ski hits about 20 or so it boggs down Impellers look good!

 

[Cobra Jet Steering LLC]

May have an internal exhaust leak, try running with the seat off and see if it improves, if it does you need to look for an exhaust leak.
Another cause could be a bad fuel switch very common on 2 stroke skies,, completely bypass that switch and go directly to the reserve pickup on your fuel tank, if the switch is bad it either allows air in to the fuel line or it obstructs the flow of fuel and kills top end.
There is a quick way to see if you are starving for fuel. But I can't tell you how for safety reasons. The fuel starvation is most likely the issue.

 

[brownjjst]

thanks I will try as soon as it warms up a bit...

 

[brownjjst]

Ok guys had carbs rebuilt and a D Plate put in runs like a champ!! Only problem now, is my exhaust sensor comes on before I can even get to the other side of the lake. Did a little research and sounds like I need a chip to tell the exhaust that it is not hot because of the D Plate. Does that sound right?