Yamaha 800XL Losing Power

[dnicholas47]

Sorry for the lack of details, but this is second hand from my Dad. He has a 2000 XL800. The thing has been a beast for us up until recently. He had it out this weekend and it ran fine for the trip, right up to the end. My Dad said when it would get above half throttle, maybe closer to 3/4, it would lose all power. It didn't sound like anything was stuck in the impeller, and it had the same gas that had been in it for the weekend. He said it would run fine at idle and up to that throttle point, but as soon as too much throttle was applied it would basically quit. I am going to meet him this week to take a look and test it for myself, but any suggestions on what the problem could be?

 

[Cobra Jet Steering LLC]

It could be starving for fuel. or it has an exhaust leak inside the hull choking it out at speed, usually that happens around 3/4 throttle but it won't shut off like you describe it just wont go faster than 3/4 throttle

 

[Julian]

Not sure about the engine in it, but the boats are sensitive to bad spark plugs....

 

[dnicholas47]

Sorry, (and thanks for the replies) from what he said it lost power but didn't die. As soon as they released the throttle it would be okay sibling as you kept it under roughly 3/4. How would we check for an exhaust leak?

 

[bronze_10]

In a car I would say it is fuel starved! When you pull back the throttles the fuel to air ratio is right and it runs fine again... there could have been trash in the tank that it picked up. What about fuel filter?

 

[dnicholas47]

Finally got to see for myself the problem. Runs fine up to 5000 rpm (28-30mph). Between 5000-5500 it was hit or miss if it would have problems. At 6000 rpm it would lose all power. At that point I would let go of the throttle and it would be fine so long as you stayed at or under 5000 rpm.

I tried a simple solution and switched the fuel from "On" to "Reserve". It then ran fine for a couple of minutes before the problem resumed. Any thoughts?