10w30 is fine
SAE 30
MTD
MTD
MTD
313717
MTD (Modern Tool & Die)
Mine was doing the same thing, and it turned out one of the plugs was not firing, which turned to be not the plug but the coil for that side (Briggs & Stratton 18hp on an MTD 1650 lawn tractor)
if it has a Briggs engine go to briggsandstratton.com [all one word]
Cub Cadet is now made by MTD, same as Troy Bilt and several other brands.
The FIRESTONE FAIRLAWN ESTATE tractor was built by MTD for Firestone Stores. These were sturdy, well built units. I'm not sure what years these were built, but my 12HP 1968 model is identical to my 12HP 1969 MTD 149-860, except for the clutch design.
Go to the MTD Manual Archive with the number you have and enter it into the Model Number box. For the Serial Number simply type a 1. Link is below.
MTD
Find the model number tag on the snowthrower and go to:http://manauls.mtdproducts.com/mtd/public/list.jspand use a 1 for the serial number to get a manual.