Don, it's an "1981" model.

You didn't say what year, but if it has a carburetor there is a small fuel
filter inside where the fuel hose connects to the carburetor. Doesn't
sound like a fuel filter problem though, because that would likely show
up as stumbling and stalling at full throttle.

Sounds like a carburetor problem to me. (I'm going based on idles fine,
but stalls under load at low RPM). _Maybe_ the intermediate jets plugged.

I'd also check to make sure the timing hadn't slipped, and that the timing
advance is working.

Good luck with it,

Don W.

SJ wrote:

.
Got a 21" SeaRay with a 5.7L 260hp mercruiser. It's run fine all year at
least 25 hours, even without a tune-up this year. I try to sell it
today and the guy takes it out and it nearly need towed back in. It
idles ok, but when engaged in gear, bogs down and stalls if you don't
give it nearly Full throttle right off the bat. Tried new gas but not
dry gas. I know it has a Water/Fuel filter on the front right of the
motor. I haven't even looked at it yet really, but I'll change the
plugs and look at the distributor. Does it have a separate fuel
filter? Any advice for this total moron would be highly appreciated
because the guy wants to buy the boat if the problem isn't major.
Thanks, Scott