What Does Marine Fuel Injector Cleaning Cost?

Professional mail-in cleaning and flow testing for marine fuel injectors runs $20 to $40 per injector. That range comes from the published pricing of a dozen U.S. mail-in shops we checked in July 2026. At Dialed Injectors, top feed injectors are $25 each and side feed injectors are $30 each, parts and labor included. A set of six top feed injectors is $150 plus shipping, on one bill at the end of the service, and you see the full diagnostic report before you pay anything. Dialed Injectors does not charge for bad news: if an injector is at end of life, we send it back and you are not charged for the work on it.

The per-injector number is only half the quote. What lands on the final invoice depends on whether parts are included, whether adjustments carry extra charges, how shipping is billed, and when payment is due. This page covers our pricing, what the rest of the market publishes, a real sample invoice, and the questions that make any quote comparable.

Our pricing

Every price in that table includes parts and labor. Take the Yamaha HPDI: the OEM gaskets are $26 per injector plus shipping. For the OptiMax air injectors, the Teflon build kits retail between $15 and $20. Dialed Injectors has no separate line for o-rings or filter baskets, and no charge for an injector that cannot be saved. The full breakdown lives on our pricing and shipping policy page.

Pricing follows injector design because the test fixtures and parts differ by type. If you are not sure whether your engine runs top feed, side feed, or air injectors, our guide to marine injector types shows each design and which engines use them. Knowing your type also tells you which shops can take your set at all, since several mail-in services handle top feed only.

What the price includes

Every cleaning service at our bench covers the same seven steps:

• Benchmark flow test before any cleaning, so the report shows where each injector started
• Ultrasonic cleaning
• Leak-down testing
• Resistance and inductance testing on the coil
• Spray pattern analysis on an ASNU M-5000
• New o-rings and filter baskets as routine; seals, teflon rings, and pintle caps when the injector type calls for them
• A second flow test after cleaning, documented next to the pre-service results for a clear comparison of what changed

The report is delivered before payment. You read what we found, then you pay.

What the bench costs

Part of what you pay for is the machine your injectors land on. Flow testing rigs can be bought online for about $500. The ASNU machines we run cost about $10,000 each, and there are two of them on our bench. That gap is not about cleaning power. It is about measurement.

A budget rig can push fluid through an injector and show you a spray. It cannot hold calibrated test pressure, pulse the injector across the duty cycles your engine actually runs, and accurately show flow differences of a few percent that separate a matched set from a rough idle. Those few percent are the whole job. An outboard idles smooth and pulls clean because every cylinder gets the same fuel, and the only way to know a set matches is an instrument precise enough to see the mismatch.

This is why the diagnostic report matters more than the headline price. Flow numbers from an uncalibrated bench are useless. Flow numbers from a calibrated professional machine are a diagnostic you can act on. If you decide to compare shops, ask what your injectors will be tested on. The answer costs nothing and tells you most of what the per-injector price does not.

ASNU is not the only professional platform. Carbon Zapp and the GB benches that run in remanufacturing plants do serious work too. The line that matters is not the badge on the cabinet, it is whether the bench holds calibration and the results repeat.

We run ASNU for its fixture coverage across gasoline injector designs and for what it does to the numbers. The injector is tested dynamically, pulsed at the pressures and duty cycles it runs on the engine. Cleaning happens in the ultrasonic bath with the injector firing, which clears deposits a soak cannot reach. The before and after measurements come off the same calibrated platform, so the two columns in your report are directly comparable. And the results repeat: the same injector reads the same tomorrow, which is what turns a flow number into evidence.

What Yamaha HPDI service costs

A rough idle is the usual reason an HPDI set gets pulled, and HPDI injectors carry a parts cost that most quotes leave out. Each HPDI injector seals with two OEM gaskets, Yamaha part number 68F-13764-00-00, at about $13 per gasket plus shipping. Done right, both are replaced when the injector is serviced. That puts roughly $26 of OEM parts at cost on every injector before any cleaning happens, and a set of six needs twelve gaskets, which is about $156 in parts alone.

Twelve of those gaskets is real money sitting on a shelf, so most shops do not stock them. The part is frequently listed as special order or backordered even at the major online parts houses, so an HPDI job at a shop without gaskets on hand either waits on a parts order or comes back with the sourcing left to you. We keep them in stock, because turnaround is the reason customers ship to us in the first place.

Our HPDI service is priced all-in at $56 per injector. The gaskets are in the number, not a gotcha on the invoice.

What the market charges

Published pricing checked July 2026

We surveyed the published pricing pages of a dozen mail-in injector services in July 2026. Standard top feed service runs $20 to $40 per injector across the market, and most shops sit between $20 and $30. Side feed and OptiMax air service, where a shop offers it at all, runs $25 to $40.

The spread in headline prices is small. The spread in what those prices buy may not be. Several mail-in services handle top feed injectors only and will not accept side feed, hose type, or air injectors. Some bill o-rings and filter baskets as separate line items on top of the service price.

A real invoice

Here is what a common job costs at our bench, a set of six top feed injectors off a Yamaha OX66:

Shipping shows at cost on the real invoice, with no markup. The exact UPS Ground return rate for a set this size drops into that line before this page goes live.

The invoice arrives after the diagnostic report. Nothing on it is a surprise, because the report already told you what was done and what was found.

Why quotes vary

Two shops can publish the same per-injector price and send very different invoices. The gaps show up in four places.

Parts. Some shops include o-rings, seals, and filter baskets in the per-injector price. Others bill each part as its own line item, and the parts total is not visible until the invoice arrives.

Extra services. Some shops charge additional per-injector fees for adjustments or calibration beyond the base cleaning. Ask what is physically being adjusted and how the result is verified. Most port injectors have no adjustable components. Where adjustment does exist, the before and after flow numbers are the proof it worked.

Payment terms. Some shops require payment before your injectors ship back. Some shops charge an extra 3 to 4 percent to cover credit card processing fees. Others, including us, deliver the diagnostic report first and bill after, with no hidden costs.

Shipping. Return shipping can be included, billed at cost, or marked up. On a small set, a shipping markup can add more to the bill than the price difference between two shops.

None of this makes a shop dishonest. Injector pricing comes with real nuance and carve-outs for the reasons listed above. Not every customer has the patience to read three pages of context. At Dialed Injectors we have made it as simple and transparent as possible.

Questions worth asking any shop

Mail-in injector work is easy to compare once you know what to ask. These are the questions we would ask any shop, including us. Send them to any shop and ask for an upfront quote.

• Do you flow test before and after, and do I get the actual numbers?
• What machine are my injectors tested on?
• Do I see the diagnostic report before I pay or after, and is it paper or digital?
• Are parts billed at cost or marked up?
• Who is your parts supplier?
• Is there a surcharge for paying by card?
• If an injector cannot be saved, am I charged for it?
• What does shipping cost both ways, and is it marked up?

Any established shop can answer all eight in one email. The answers, not the headline price, are the quote.

When cleaning is not worth the money

Cleaning restores flow. It does not fix everything, and an honest cost page should say where the money stops making sense.

A failed coil is a replacement, not a cleaning. Resistance testing catches this on arrival, which is why it runs before cleaning in our process. If a coil is open or out of specification, no amount of cleaning brings it back, and you should not pay a cleaning price for that injector.

A cracked body is a replacement. Cracks in the injector body are a fuel leak and a fire risk. Cleaning does not repair plastic or metal.

Cleaning is not a rebuild. Replacing o-rings, seals, and filter baskets restores the serviceable wear parts. The internals of a modern injector are not user-serviceable or shop-serviceable components, and a shop claiming to rebuild them is describing cleaning with a different word.

If your injectors test fine, that is worth knowing too. A set that flows within specification and matches across cylinders rules out the injectors and points your diagnostic at the rest of the fuel system.

We service gasoline injectors only. Diesel injectors are a vastly different technology on completely different equipment, with service benches built for pressures upwards of 20,000 psi. It's a different animal.

For most marine sets, the math favors cleaning. New OEM outboard injectors commonly cost well over $100 each, discontinued applications run far higher, and a full set purchased to chase one bad injector is the most expensive way to solve the problem. Cleaning with real flow data tells you which injectors, if any, actually need to be replaced. The same math favors a cleaning interval over a rescue: injectors serviced on schedule cost the same per injector as injectors serviced after a summer of rough running, and only one of those summers was any good.

Frequently asked questions

Is it cheaper to clean fuel injectors or replace them?

Cleaning is almost always cheaper. Professional mail-in cleaning and flow testing runs $20 to $40 per injector, while new OEM outboard injectors commonly cost well over $100 each. Cleaning with flow data also tells you which injectors, if any, actually need replacement, so you never buy a full set to fix one problem.

What happens if my injectors test fine?

A clean result is a useful result. If your injectors flow within specification and match each other, the report tells you to look elsewhere in the fuel system, and you have ruled out the most common wear item.

Do I pay for an injector that cannot be saved?

No. If an injector fails testing and cannot be restored, we do not charge for the work on that injector. The diagnostic report shows exactly what failed so you can replace only that unit.

Why do quotes for the same set of injectors vary so much?

The per-injector price is only part of the bill. Shops differ on whether parts are included or itemized, whether adjustments carry extra charges, whether card payments carry a surcharge, and whether return shipping is billed at cost or marked up. Two quotes with the same headline number can arrive as very different invoices.

Is shipping included in the price?

No, and that is on purpose. Free return shipping means the cheapest service the shop can buy, and the cheapest service is not insured. We bill shipping at cost on the one invoice you receive after the diagnostic report, and about one in three customers adds UPS insurance, also at cost, through our shipping tool. Injectors are small, dense, and expensive to replace. We would rather show you the real shipping line than hide a cheap one.

Why does Yamaha HPDI service cost more than other injector types?

HPDI injectors require two OEM gaskets per injector if done right, Yamaha part number 68F-13764-00-00, at about $13 per gasket plus shipping. Replacing both at service is the correct procedure, which adds roughly $26 in OEM parts to each injector. Shops that quote HPDI at a standard side feed price are either skipping the gaskets or adding them to the invoice later.

How long does the service take?

Injectors are on our bench for two days. Total time away from your engine is bench time plus shipping both ways, which for most customers in the eastern half of the country is four to six days door to door on UPS Ground.

You pull the injectors, we do the bench work. Our pricing page has the full service breakdown, and when you are ready, ship your injectors.