The 15-30 'F' is probably the neatest Rumely in my opinion. The 10 inch bore, 12 inch stroke, single cylinder engine is very similar to that of an 'E' (also runs at 350 RPM). Actually some of the parts even interchange. The 'F' is kind of half of an 'E'. The tractor weighs 16,000 lbs. Like the 'E', most used low tension ignition, but later 18-35's had optional high tension systems. Type 'F' production began in 1911 starting with SN 5001 & went to 1918 with none built in 1915. 3,855 tractors were made in that time. Out of that number, 111 survived. That's a 2.88% survival rate. For more SN info on the 15-30, CLICK HERE.