merc 5.7 issues

[Godfirst]

Just got back from the lake yesterday and the boat only at full throttle went about 22mph at 3400rpm's the boat has a merc 5.7 260 alpha 1 sterndrive, had the drive serviced and has the propper prop and now the boat will not run properly, use to be a 40mph boat, any comments or questions greatly appreciated.
Thanks

 

[Godfirst]

Re: merc 5.7 issues

The boat is a 1987 24sport vee

 

[FunInDuhSun]

Re: merc 5.7 issues

First thing to check is to make sure you unhooked the trailer from the boat!
Next likely suspect would be the gas filter.