Snowmobile Repair: Snowmobile fuel tank, tillotson carbs, arctic cat panther

Question
I have a 1970 Arctic Cat Panther (P399K)that I'm trying to restore.  On the top of the fuel tank, there was a rubber part that had a schrader vavle in it.  The part has since disintregrated.  Do you know what purpose this part served?  Also the Gas Tank elbow (connection for fuel lines) has two connections on it.  I've looked at other tank diagrams and they only have one connection for one fuel line coming out of the tank.  Do you know why this particular tank has two lines coming out of it?  The fuel lines have also disintregrated so I don't know which fuel lines going from the tank elbow go to where on the carb?

Mike

Answer
Hello Mike,

 You have a pretty rare, neat old sled there! I'm not sure what that exact purpose of the vale is, but most probably acted as a vent. Now, as far as the two fittings on the elbow, the reason for that is, the 1970 Panther used 5 different carburetors, not sure exactly why Arctic Cat did that. Any how, it used the 4 Different Tillotson Diaphragm carbs, and 1 Walbro, the BDC-3. With the Tillotsons, there is 2 hoses, one goes to the carbs diaphragm pump, and one comes back out of it, and is a return line. Verify with the carb, to see what carb it has, ( here is a link for verification and parts:  http://www.brownsleisureworld.com/Parts/SNOWMOBILE/1970/1970Panther/GASIGNITION....   ) and then go from there. Now, your carb will also have a impulse line that goes from the carb to the engine, and uses the engines impulses to power the pump, check that to be sure it isn't leaking or damaged. Also, for the 2 fittings on the gas tank, it shouldn't make a difference which line you use to hook up to the carb, just hook up one to each fitting on the carbs, using new fuel lines, but if it won't start, or isn't getting gas, swap the lines. Just be sure that you don't hook a fuel line up to the impulse line. For easy verification as far as to which carb you have, the Tillotson carbs diaphragm pump on the bottom, where as the Walbro has a squared off appearance. The carb should have the name on it, though. Hope this helps you out, let me know if I can help you out with any questions you might have at all! Good luck with the Cat! --Arcticatman