Is this normal for mrec?

[phatdaddy]

Merc makes a special set of muffs for their motors that seem to work best. actually 2 pieces that have a rod & spring clip to pass thru the motor & hold them together. probably my imagination, but mine seems to run in more "in the water" mode that the conventional muffs. don't know if they are worth the expense, but you don't have to worry about them vibrating off while the motor is running..