Lack of Power 2004 Hurricane 198R Fundeck
In July of this year we bought a used 2004 Hurricane Fundeck 198R with a Yamaha F115 outboard motor. The previous owner had about 100 hours on the boat but it had sat unused for we think about a year. We charged the battery and filled the tank with gas and launched and the boat would not exceed 10 mph on the water and ran at around 2000 rpm. We took it in to get serviced and they replaced a throttle control that was stuck around 60 percent. We launched the boat again and it work great, around 30mph, for about a half an hour and then went back to only going around 10 mph but around just over 3000 rpm.
I am not a boat person and am wondering what could be wrong. Has anyone run into this or have any ideas what it could be?