I thought I had posted this correctly but it's not showing up on the list.....sorry if this is a repeat.<br /><br />We bought our first boat last week. It's a 1991 Bayliner Trophy 2002 Walk Around with a 1991 150 HP Force motor. When we went to the broker to buy her the motor wouldn't run higher than 3000 RPM. The broker said that it was probably because the boat had been in storage for several years and needed a tune-up. I requested that they do this and a compression check as well. When I went back to test it again the motor ran like a dream. I ran her at top speed (around 5000 rpm) for about an hour. There seemed to be no problem. The compression check showed everything within limits with cylinder #5 being a little lower than the rest. I bought the boat and brought her back to Jocassee where my family was spending the week. The first day was great. The boat ran fine...until the afternoon when all of a sudden the rpms dropped to 4000 then 3000 then eventually to 2500. I took the boat to a local mechanic and he pulled the plugs. The plugs were ugly brown, he said they were fouled. I told him that they were supposed to have been changed in the tuneup that the broker did. He changed them, did another compression check. His check was about the same as what the previous check had been. The motor ran great after he put new plugs in, for about an hour. The same thing happened; it ran fine then dropped rpm just like before. I found that if we stopped the engine and fished or something for 10-20 minutes I could turn the motor back on and it would go back to top speed. I also found that if I run the boat at top speed she lasts about 10 minutes before dropping RPMs and if I ran the boat at 4000-4200 RPM she would run for 30 to 40 minutes without losing any power.<br /><br />Any suggestions? Guesses?<br /><br />Thanks,<br /><br />Steve
