By Outrider Editorial Team · Updated August 20, 2026
Official definition
This U.S. industry comprises establishments primarily engaged in manufacturing internal combustion engines (except automotive gasoline and aircraft).
FY2025 obligations
$755.1M
Contract actions
48,729
IDVs
562
Top buying agencies
- Department of Defense$685.7M
- Department of Homeland Security$53.9M
- Department of Veterans Affairs$12.6M
- Department of the Interior$1.7M
- Department of Commerce$875.0K
FY2025 federal contract obligations, USAspending.gov
NAICS 333618 obligated $755 million in FY2025 across 48,729 contract actions, an average of about $15,500. DoD is $686 million, DHS $54 million for Coast Guard cutter and boat powerplants, VA $13 million for facility generators. The transaction profile makes the business model obvious: this is spares and small-lot demand for engines already installed in ships, generators, and ground equipment.
What belongs here
Internal combustion engines other than automotive gasoline and aircraft. Marine diesels, generator prime movers, and industrial engines belong here, along with their parts.
- Aircraft engines and engine parts, including propulsion overhaul, are 336412.
- Clutches, couplings, bearings, and drive chains are 333613.
- Repairing engines in place as a service is 811310.
Competing in this code
562 IDVs against 48,729 actions is the signature of DLA long-term contracts plus automated small-order response. At $15,500 per action, any manual quoting process is unprofitable, and the vendors who succeed hold approved source status on specific national stock numbers and respond electronically. The high-value niche inside the code is obsolete and low-demand engine parts for legacy marine and generator platforms, where the original manufacturer has exited and a qualified alternate source faces essentially no competition on repeat buys.
Frequently Asked
NAICS 333618 questions, answered.
What is the SBA size standard for NAICS 333618?
SBA sets it at 1,500 employees, counted as a 24-month average headcount across your company and every affiliate, not revenue. At or under that number you are small on NAICS 333618 solicitations and eligible for the set-asides in this code.
Which agencies buy engines and engine parts under NAICS 333618?
FY2025 obligations: DoD ($686 million), DHS ($54 million), VA ($13 million), Interior ($2 million). DHS's share is Coast Guard cutter and boat powerplants, and VA's is facility standby generation, both of which behave like commercial industrial markets.
What business model works in NAICS 333618?
Approved source status on specific national stock numbers plus automated electronic quoting. The code ran 48,729 actions in FY2025 at an average of $15,500, supported by 562 IDVs. Manual quoting costs more than the award is worth, so profitability depends entirely on response automation and existing part approvals.
What is the most profitable niche in NAICS 333618?
Obsolete and low-demand parts for legacy marine and generator platforms. When the original manufacturer exits, a qualified alternate source faces almost no competition on repeat buys, and the government has no substitute. Qualifying those parts is slow, which is precisely why the position holds.
Register Under NAICS 333618
Classify your business correctly to maximize visibility to federal buyers and access small business set-asides.
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