Sound Down? The on-going attempt...
As Loren alluded, the OEM 'stuff' Ericson used on these Olsons is flaking & crumbling, offering little decibel resistance and creating a big mess whenever it's touched, rubbed or breathed on.
The 1st attempt, surprisingly successful (as that rarely happens on the 1st go) was to re-insulate the small panel that allows access to check the oil level and murmur sweet nothings in the girl's ear, the latter in the hope that Iron Genny (she's ok with that nick name) will remain reliable.
Because that small test worked (neat, tidy, not crumbly), the next was the removable tray above the engine. Just larger, but the same installation system as the little panel.
Next up, while cringing, was the port/sb side surfaces, accomplished by removing as little as possible of the wiring and control cables to affix the insulation in tight quarters (at best) or 'not a chance' (at worst). The decibels increased as the 'sweet murmurs' changed to questions of linage and blaming those responsible for naval design.
Eventually, port and starboard received all new sound dampening material. The dB App on my Apple proved there is a difference (wonderful thing, at times, this technology stuff!).
The final step, which hasn't happened, WAS an attempt to pull the fiberglass steps, schlepp it home to the shop last winter and redo all that material, comfortably, with plenty of room and time. Unfortunately, that same naval architect somehow figured a way to get the steps in, but allowed no way for them to be removed (like building a boat in a basement). A friggin' 3-d Rubik's Cube that proved unsuccessful, no matter how the step assembly was rotated, positioned or started. Nightmare, and then surrender. Not happening, not in the home shop. Plan B.
I sprung for the recommended tape, trying to avoid repeating the process again due to 'cheap'. Right decision.
Next up...another attempt to locate the low oil pressure buzzer. The light works, but no sound, which, given a choice, the inverse would be preferred. Oh well...
Hope this helps someone. Take care.