Me and my brother have had this boat for about 2 months. When we first got it, it ran great, took it on a few weekend trips everything was great, turned 5900 RPM at about 55 mph. Now, it won't go above 2000 in gear. Tried tilting the engine, changed plugs, charging system, fresh gas, everything. I have not yet checked the plugs for spark, and it runs great except for this one little problem. The boat is 1981 Ranger 335V, with a 1981 Merucry 115 hp straight six. Any help before I haul her into the shop? The prop does turn freely in neutral, so I don't think anything is bent.
Thanks
Grimjack