exhaust warning light

[gavacho]

I just bought a 2007 sea doo 180 challenger se with the 215hp. When I bought it the boat had only 2hrs on it. I took the boat out later that week to the river and it started fine. As soon as i went 5k-6k rpms it flash exhaust warning and made a continuse beeping noise until I shut off the boat. The boat restarted fine but when i started to accelerate it did it again. I dock the boat and took it home. I got under the boat and removed a small stick that was stuck in the impeller. I went out today and as soon as i reach 5k-6k rpms it did it again. This time I dock the boat and looked under and saw nothing. What could be causing this issue? A sensor? Is it something that I could do myself? Please help! I'm taking the boat to have the 10hr service done to it on wednesday which is going to cost me $230 to do. I can't afford to have the service work and have them figure out whats wrong with the boat. Its arm robbery what they charge. I can't believe they can get away with that. Any help is greatly appreciated! Thanks

I forgot to add that the sales person when he brought the boat to me he ran the boat without running water throught the boat engine/cooling system. Could that have cause some damage to trigger that sensor to go off?