high rev rattling (poss prop cavitation)

Posted: Mon Jan 09, 2012 7:32 pm

hi , im after some help . my seahog shorty with a 40hp 2 stroke mariner has started to rattle when at higher speeds but goes when i back off then re apply revs but now each trip its getting more noticable. the trim tab plate was loose above prop and have tightened up and now its even more noticable. its almost like a cross between pinking and a snapped off exhaust dragging alomg the road. i dont notice a power drop and its not a spun prop but find it hard to believe that cavitation can cause a noise that loud. one of the blades does look to have a different curve and the edges could use a file but no pitting on the blade but the trim tab fine has signs of pitting???

thanks in advance jamie

Posted: Mon Jan 09, 2012 9:01 pm

Have you tried Doel fins fitted to the cavity plate?
Cheers
keith big grin

Posted: Mon Jan 09, 2012 9:12 pm

ive had the boat 3 years and its always done it at full throttle but i never go anywhere at full , just get her on the plain and back it off. its always had dole fins fitted and its becoming more apparent at cruising speeds. cant find much on the net about the noise it makes just the effects!!!!!!!

Posted: Tue Jan 10, 2012 8:00 pm

have you checked your transom mount bolts or it could be play in the mount to middle section see if the engine moves when you pull it about by hand

Dave big grin