Modifying a saw: what the federal tampering rules and engine warranty rules say

This page reports what the official source says. It is not legal advice: ask the office named here. It covers the federal rules in Title 40 of the Code of Federal Regulations as printed on the eCFR. It does not cover rules of individual states, the United Kingdom or the European Union, and it says nothing about how to change a saw. The glossary of saw chain, bar, fuel and battery words and the page on fuel mix and ethanol are the nearest pages on the saw itself.

Which engines the rules cover

Section 1054.1 says Part 1054 applies to new nonroad spark-ignition engines with a maximum power at or below 19 kW. A table in that section gives the model year it starts for handheld engines as 2010, for non-handheld engines under 225 cc as 2012, and for non-handheld engines of 225 cc or more as 2011. The section adds that tampering and defeat-device prohibitions continue to apply to older engines that met Phase 1 or Phase 2 standards.

The tampering prohibition, section 1068.101(b)

Section 1068.101 opens with a statement that it lists prohibited actions and maximum civil penalties under 42 U.S.C. 7522 and 7524, with the figures applying as of August 1, 2016 and open to adjustment under 40 CFR part 19. Paragraph (b) is headed as applying to everyone. Two of the prohibitions in it are set out here.

Tampering, (b)(1). No one removes or renders inoperative any device or element of design installed on or in an engine in compliance with the regulations before its sale and delivery to the ultimate purchaser. After that sale, no one knowingly removes or renders it inoperative. The paragraph's own examples include running an engine on incorrect fuel or engine oil that renders the emission control system inoperative. It says the section on rebuilding engines, 1068.120, describes how this applies to rebuilds.
Defeat devices, (b)(2). No one knowingly manufactures, sells, offers to sell or installs a component that bypasses, impairs, defeats or disables the control of emissions of a regulated pollutant, except where the standard-setting part explicitly allows it.

The printed civil penalty figures are in the table.

Violation	Maximum civil penalty as printed
Tampering by a manufacturer or dealer	US$44,539 for each engine or piece of equipment
Tampering by anyone else	US$4,454 for each engine or piece of equipment
Selling or installing a defeat device component	US$4,454 for each component

The tampering paragraph lists three situations where the prohibition does not apply: a repair where the engine is restored to proper functioning when the repair is done, a modification to respond to a temporary emergency with the engine restored as soon as possible, and a modification of new engines that another manufacturer has already certified, which are then recertified under the modifier's own family.

The competition exemption, section 1068.235

Section 1068.235 covers nonroad engines and equipment used solely for competition. Under paragraph (b), engines modified after being placed in service in the United States so that they are used solely for competition are exempt without any request. It says this exemption applies only to the two prohibitions in 1068.101(b)(1) and (b)(2), and holds only as long as the engine or equipment is used solely for competition. It adds that the original emission labels are destroyed and that anyone who lends, leases, sells or gives such an engine to someone else tells the new owner in writing that it may be used only for competition.

What the small engine rule asks of the maker

Section 1054.115 sets requirements on engines certified under Part 1054. Crankcase emissions are not discharged directly into the open air, with a stated exception for snowthrower engines. Engines with adjustable parameters meet the rule for any adjustment in the practically adjustable range, and the section allows a request to limit idle-speed or carburetor adjustments to a smaller range. It also bars engine makers from fitting a defeat device, defined as an auxiliary emission control device that reduces the effectiveness of emission controls in conditions the engine can reasonably be expected to meet in normal use.

The emission warranty, section 1054.120

Section 1054.120 requires the certifying maker to warrant to the first purchaser and each later purchaser that the engine meets the rule when sold and is free from defects in materials and workmanship that could keep it from meeting the rule. The minimum warranty period is two years, starting on the date of sale. The section lets EPA set a shorter period for handheld engines in severe service in seasonal equipment, if EPA finds they are likely to run more than their useful life hours within 24 months, and the maker has to ask for that in its certification application. The warranty covers every component whose failure would raise emissions, even a component made by another company. The maker may deny a claim where the operator caused the problem through improper maintenance or use as described in section 1068.115. That section lists claims a maker may not deny, including claims based on the use of a fuel commonly available where the equipment operates, unless the written maintenance instructions say the fuel would harm the emission control system and operators can readily find the proper fuel.

What these sources leave out

The sections above do not mention chainsaws by name or any particular change to a saw, and they give no list of parts.