Well, I have a Bass Tracker PT185 with a 90hp Mercury 05 model. WOT with Black Max 5400-5500rpms and 44mph on gps with me only in the boat. 5200-5300rpms and 41mph fully loaded.<br /><br />I switched from a 12.75x21P Black Max to a 13.25x21P Rapture.<br /><br />Results:<br />Hole shot: Good with vent holes out and motor trimmed fully down.<br /><br />Cruising Speed and Control: Excellent, the lift was like night and day. The boat set much higher on the water and handled well.<br /><br />Top Speed: Good, I had the boat loaded with 3 people and gear. RPMs were a little lower until I trimmed the motor. With it fully trimmed before blow out I get about 5400rpms with 42 on the GPS which is 1-2mph faster than it was before with the other prop.<br /><br />Problem:<br /><br />Idle speed: Not so good. From starting the motor from a cold state everthing was fine until I put it into gear, it had alot of vibration and kind of chug a lugged intermittently until I reached 1600rpms and it smoothed out and would act normal. At the slowest rpms it knid of sounded like it wanted to slip out of gear.<br /><br />After slowing down from a being plained off it runs better all the way down to 750rpms. but intermittely gets rougher.<br /><br />It kind of acts like it wants to die it shakes alot and vibrates, then it will stop for a second or two then run rough for a while until the short period it gets better for a second. But if I run it up to 1600rpms it's good.<br /><br />Note: It did not do anything like this with the other prop.<br /><br />If I'm not mistaken I beleive I read a thread on hear recently that somone described something similar with their new prop.<br /><br />Any ideas why it's doing this and what I can do to fix it?
