Repairing Old Pressure-style Gas Tank

[Carlasdaddy]

I have an old pressure-style tank for my 1958 Evinrude 7.5 motor that has some old gas in it. I need to remove 2 screws to drain the tank, but they are frozen tight. Putting penetrating oil on them is no help as they have a sealing washer under the head. I tried using an impact driver, but that didn't work, either. Anybody got any suggestions or tips to remove these screws?

 

[nccatfisher]

You may have to drill them out. Go the left hand drill bit route and hope the combination of heat generated from drilling possibly will twist them in the process, if not at least they will be preheated for the easy out.

 

[Pappy]

Those are good tanks. Do yourself a favor and do the diaphragm as well as new seal washers, the cork gasket, and the few other seals needed to do it right. Will pay off for a long long time.
On your 7 1/2......that is one engine that I would highly recommend running on a 20:1 mixture. Why? For some reason that particular engine tended to fail #1 connecting rod with lighter mixtures. Ask me how I, plus several others, know! Properly tuned you will or should not notice any increase in smoke output.

 

[Ronbedard57]

HI,
Those old tanks had a collar around the fill hole to help prevent overfilling. (you probably know that). That's why there's a screw that says "drain" next to it. Drilling, heating, etc. while there's any trace of gas left in there is dicey. Get out all you can with a turkey baster, and pour in a handful of sweeping compound or sawdust to soak up every drop. Some degreaser and a fresh water rinse should make the tank safe for whatever comes next. The bolts you're trying to remove are pretty small gauge, so drilling for an extractor might be difficult. I once removed a stuck bolt by building a putty "dam" around it that I filled with penetrant. Then left it over-night with a wrench tensioned with a bungee cord.
Can't be too careful.
Good luck