90hp sportsjet power loss

[damage inc]

hay iv got a 90hp sportsjet oe067119 in an 94 bayliner jazz. last year i was running without intake grate/screen and BAMM! staled moter. after gitting it started boat inpeller/prop was damage so i hobbeled it back in.this year got new impeller had shaft reworked to fit splined rather than threded,So get in the water and cant get up to speed.Big power loss takes time but do get up to 32,(45mph reg) bogs in turns just missing power,after this i took it in to a shop they said it had no compression in #1,but mec also implyed he had just did a compresion and nothing as to keep down 75.00 hour rate,now i today started too pull the powerhead by book ,and found both exhaust boot clamp loose like u could spin them freely/Would this cause my prob& give low compresion?