Re: Need Manual on Renken 1780 Seamaster!!
I have a 1990 Renken 1880 Seamaster CC with an outboard. The gas tank is below the center console on my model. You should look for an access port on the floor inside the console. It should open to an area in the proximity of the fuel level sending unit. You may be able to get in through there. If not, remove the console, open the large rectangular access panel, and you will have full access to the fuel tank. All of this is based on the assumption that your Renken is similar to mine.
If the screwdriver does not block fuel flow through the filler neck, I'd just leave it in there. But I'm lazy.