Re: Rattle on decelration
'97 is tuned to run fine on regular. 87 octane. So I'd forget the decel knock and prop ratcheting. Almost all 2strokes have a reed flutter at around 2500 to 3000 rpms, but you'd hear that accelarating also. Ya got me on that one. Any chance the motor has been at some time overheated and you're hearing some piston skirt noise? There are many possibilities, and noises (even from the gearcase) transmit through the motor and can be hard to pin down. If the motor ever injested any water, you could have some rod or bearing damage, and that can be fatal. When in doubt, always start at the beginning--see what you have for cylinder compression. 15% or more diviation among the 4 is maximum, and they should all be very close--plus or minus about 10psi. Also, are you running a stainless prop? If so, what kind?