Snow Cats tend to sit alot, kinda like your lawn mower in the winter. The fuel turns in to shellac. The really primo buy's are the EX power company or EX Phone company machines. They get used when there is a big storm, then they sit sometimes for several seasons and develop fuel problems. Of the 23 tracked vehicles I've owned, almost all of them suffered from fuel, or more correctly OLD FUEL problems.
For ST4, Snow Trac, Snow Master, & Trac Master I recommend that you rip the original under the back seat tank or tanks out and discard them. Put 'Boat' tanks on one or both of the front fenders. This serves multiple purposes.
1) clean out the fuel tank.
2) replace the filter.
3) at a minimum consider taking the carb off and have it rebuilt or at least cleaned.
4) Replace the fuel line(s).
5) replace the fuel pump.
For all those with VW powered units, the fuel pump is cheap, and easy to change out. If you are the proud owner of a machine that has a Chrysler Flat-Head Six, it will usually run well on old smelly gas. All others should drain out last years gas or run the machine dry at the end of the season. 2) replace the filter.
3) at a minimum consider taking the carb off and have it rebuilt or at least cleaned.
4) Replace the fuel line(s).
5) replace the fuel pump.
For ST4, Snow Trac, Snow Master, & Trac Master I recommend that you rip the original under the back seat tank or tanks out and discard them. Put 'Boat' tanks on one or both of the front fenders. This serves multiple purposes.
1) eliminates needing an auxiliary fuel pump. They are obnoxious, noisy, and a slight fire hazard. As the tank is in a higher position it will actually run with a defective fuel pump.
2) It get's the fuel out of the inside of the cab which is a fire hazard especially if you have any smokers. And you gain some valuable inside storeage space.
3) Some Snow Trac tanks had leaded seams and if they leak it ruins your floor matting.(Been there, had it happen, didn't like it!)
Junk any original copper fuel line and replace it with hose. In the ST4 engine compartment it gets hot and this leads to vapor lock. Many owners resorted to an additional electric fuel pump, just to get the machine to start after a long hill climb. The 12 gallon Boat tank with the quick connect and a squeeze primer pump is my favorite. Instead of having to pour gas into the machine you simply take just the tank to the gas station with you. Also If you leave the machine parked in a public place overnight, such as many cabin owners are forced to do, you can either lock the tank up inside the machine or take it with you. This helps to preclude theft and joy riders. A dealer of my aquaintance who restores one machine a year, now takes one of the boat tanks complete with hose and squeeze bulb with him all the time and has had to resort to using it. Also carry a fire extinguisher. It's a long walk out!2) It get's the fuel out of the inside of the cab which is a fire hazard especially if you have any smokers. And you gain some valuable inside storeage space.
3) Some Snow Trac tanks had leaded seams and if they leak it ruins your floor matting.(Been there, had it happen, didn't like it!)
