I have been a Califronia State Certified Arbitrator for over 20 years... the majority of my cases are automotive because they typically are high dollar purchases.
Tractors would also be a high dollar purchase and as long as the item is for personal, non-business use, it applies.
There are both Federal and State Statutes.
The California versions is the Song-Beverly Consumer Warranty Act and covers just about any "Consumer" purchase and is very specific as to when it does not apply... Buying something AS-IS is specifically mentioned as being excluded.
Basically any item offered with a warranty is covered.
Here is excerp...
"A buyer of this product in
California has the right to have this product serviced or repaired
during the warranty period. The warranty period will be extended for
the number of whole days that the product has been out of the buyer's
hands for warranty repairs. If a defect exists within the warranty
period, the warranty will not expire until the defect has been fixed.
The warranty period will also be extended if the warranty repairs
have not been performed due to delays caused by circumstances beyond
the control of the buyer, or if the warranty repairs did not remedy
the defect and the buyer notifies the manufacturer or seller of the
failure of the repairs within 60 days after they were completed. If,
after a reasonable number of attempts, the defect has not been fixed,
the buyer may return this product for a replacement or a refund
subject, in either case, to deduction of a reasonable charge for
usage. This time extension does not affect the protections or
remedies the buyer has under other laws."
Song Beverly - Dept of Consumer Affairs - Arbitration Certification Program (Lemon Law)
On the Federal Level it's Magnuson-Moss Warranty Act
Magnuson
Sorry for my short answer as I'm away from my computer.