'96 Sea-Doo GTI running rich

As noted, I have a 1996 Sea-Doo GTI that seems to be running rich on gas. It seems I can only get about 1-2 hours of ride time on it now which I used to could ride all day on a tank. When behind the jet ski, you get a strong gas odor as well. I have never noticed it being as strong. Maybe it's my imagination.. Is it possible to have this problem? What do I need to do to fix it? My Sea-Doo repair shop is backed up and I would like to use it this weekend if possible.

I also went into a non dealer repair shop today and the guy just suggested that all I need for summer tune up is to change the spark plugs.

Thanks for any advice.

-Todd